RISC-V: Add bfd/cpu-riscv.h to support all spec versions controlling.

Make the opcode/riscv-opc.c and include/opcode/riscv.h tidy, move the
spec versions stuff to bfd/cpu-riscv.h.  Also move the csr stuff and
ext_version_table to gas/config/tc-riscv.c for internal use.  To avoid
too many repeated code, define general RISCV_GET_SPEC_NAME/SPEC_CLASS
macros.  Therefore, assembler/dis-assembler/linker/gdb can get all spec
versions related stuff from cpu-riscv.h and cpu-riscv.c, since the stuff
are defined there uniformly.

bfd/
    * Makefile.am: Added cpu-riscv.h.
    * Makefile.in: Regenerated.
    * po/SRC-POTFILES.in: Regenerated.
    * cpu-riscv.h: Added to support spec versions controlling.
    Also added extern arrays and functions for cpu-riscv.c.
    (enum riscv_spec_class): Define all spec classes here uniformly.
    (struct riscv_spec): Added for all specs.
    (RISCV_GET_SPEC_CLASS): Added to reduce repeated code.
    (RISCV_GET_SPEC_NAME): Likewise.
    (RISCV_GET_ISA_SPEC_CLASS): Added to get ISA spec class.
    (RISCV_GET_PRIV_SPEC_CLASS): Added to get privileged spec class.
    (RISCV_GET_PRIV_SPEC_NAME): Added to get privileged spec name.
    * cpu-riscv.c (struct priv_spec_t): Replaced with struct riscv_spec.
    (riscv_get_priv_spec_class): Replaced with RISCV_GET_PRIV_SPEC_CLASS.
    (riscv_get_priv_spec_name): Replaced with RISCV_GET_PRIV_SPEC_NAME.
    (riscv_priv_specs): Moved below.
    (riscv_get_priv_spec_class_from_numbers): Likewise, updated.
    (riscv_isa_specs): Moved from include/opcode/riscv.h.
    * elfnn-riscv.c: Included cpu-riscv.h.
    (riscv_merge_attributes): Initialize in_priv_spec and out_priv_spec.
    * elfxx-riscv.c: Included cpu-riscv.h and opcode/riscv.h.
    (RISCV_UNKNOWN_VERSION): Moved from include/opcode/riscv.h.
    * elfxx-riscv.h: Removed extern functions to cpu-riscv.h.
gas/
    * config/tc-riscv.c: Included cpu-riscv.h.
    (enum riscv_csr_clas): Moved from include/opcode/riscv.h.
    (struct riscv_csr_extra): Likewise.
    (struct riscv_ext_version): Likewise.
    (ext_version_table): Moved from opcodes/riscv-opc.c.
    (default_isa_spec): Updated type to riscv_spec_class.
    (default_priv_spec): Likewise.
    (riscv_set_default_isa_spec): Updated.
    (init_ext_version_hash): Likewise.
    (riscv_init_csr_hash): Likewise, also fixed indent.
include/
    * opcode/riscv.h: Moved stuff and make the file tidy.
opcodes/
    * riscv-dis.c: Included cpu-riscv.h, and removed elfxx-riscv.h.
    (default_priv_spec): Updated type to riscv_spec_class.
    (parse_riscv_dis_option): Updated.
    * riscv-opc.c: Moved stuff and make the file tidy.

include/opcode/riscv.h

@@ -349,71 +349,6 @@ struct riscv_opcode
   unsigned long pinfo;
 };
 
-/* The current supported ISA spec versions.  */
-enum riscv_isa_spec_class
-{
-  ISA_SPEC_CLASS_NONE,
-
-  ISA_SPEC_CLASS_2P2,
-  ISA_SPEC_CLASS_20190608,
-  ISA_SPEC_CLASS_20191213,
-  ISA_SPEC_CLASS_DRAFT
-};
-
-#define RISCV_UNKNOWN_VERSION -1
-
-/* This structure holds version information for specific ISA.  */
-struct riscv_ext_version
-{
-  const char *name;
-  enum riscv_isa_spec_class isa_spec_class;
-  int major_version;
-  int minor_version;
-};
-
-/* All RISC-V CSR belong to one of these classes.  */
-enum riscv_csr_class
-{
-  CSR_CLASS_NONE,
-
-  CSR_CLASS_I,
-  CSR_CLASS_I_32, /* RV32 only.  */
-  CSR_CLASS_F, /* F extension only.  */
-  CSR_CLASS_DEBUG /* Debug CSR.  */
-};
-
-/* The current supported privilege spec versions.  */
-enum riscv_priv_spec_class
-{
-  PRIV_SPEC_CLASS_NONE,
-
-  PRIV_SPEC_CLASS_1P9P1,
-  PRIV_SPEC_CLASS_1P10,
-  PRIV_SPEC_CLASS_1P11,
-  PRIV_SPEC_CLASS_DRAFT
-};
-
-/* This structure holds all restricted conditions for a CSR.  */
-struct riscv_csr_extra
-{
-  /* Class to which this CSR belongs.  Used to decide whether or
-     not this CSR is legal in the current -march context.  */
-  enum riscv_csr_class csr_class;
-
-  /* CSR may have differnet numbers in the previous priv spec.  */
-  unsigned address;
-
-  /* Record the CSR is defined/valid in which versions.  */
-  enum riscv_priv_spec_class define_version;
-
-  /* Record the CSR is aborted/invalid from which versions.  If it isn't
-     aborted in the current version, then it should be CSR_CLASS_VDRAFT.  */
-  enum riscv_priv_spec_class abort_version;
-
-  /* The CSR may have more than one setting.  */
-  struct riscv_csr_extra *next;
-};
-
 /* Instruction is a simple alias (e.g. "mv" for "addi").  */
 #define	INSN_ALIAS		0x00000001
 
@@ -488,9 +423,5 @@ extern const char * const riscv_fpr_names_abi[NFPR];
 
 extern const struct riscv_opcode riscv_opcodes[];
 extern const struct riscv_opcode riscv_insn_types[];
-extern const struct riscv_ext_version riscv_ext_version_table[];
-
-extern int
-riscv_get_isa_spec_class (const char *, enum riscv_isa_spec_class *);
 
 #endif /* _RISCV_H_ */