MIPS/opcodes: Also set disassembler's ASE flags from ELF structures

Respect any ASE flags recorded in ELF file structures for the purpose of
selecting instructions to be disassembled, preventing code from being
hex-dumped even though having been clearly indicated as valid at the
assembly time.  Use date from the MIPS ABI flags structure if present,
and otherwise there may be an MDMX ASE flag set in the ELF file header.
For backwards compatibility only set extra flags and do not clear any,
preserving all previously set by the architecture selected to be
disassembled for.

	include/
	* elf/mips.h (Elf_Internal_ABIFlags_v0): Also declare struct
	typedef as `elf_internal_abiflags_v0'.

	bfd/
	* bfd-in.h (elf_internal_abiflags_v0): New struct declaration.
	(bfd_mips_elf_get_abiflags): New prototype.
	* elfxx-mips.c (bfd_mips_elf_get_abiflags): New function.
	* bfd-in2.h: Regenerate.

	opcodes/
	* mips-dis.c (mips_convert_abiflags_ases): New function.
	(set_default_mips_dis_options): Also infer ASE flags from ELF
	file structures.

	binutils/
	* testsuite/binutils-all/mips/mips-ase-1.d: New test.
	* testsuite/binutils-all/mips/mips-ase-2.d: New test.
	* testsuite/binutils-all/mips/mips-ase-3.d: New test.
	* testsuite/binutils-all/mips/mips-ase-1.s: New test source.
	* testsuite/binutils-all/mips/mips-ase-2.s: New test source.
	* testsuite/binutils-all/mips/mips.exp: Run the new tests.

include/elf/mips.h

@@ -1101,7 +1101,7 @@ typedef struct
   unsigned char flags2[4];
 } Elf_External_ABIFlags_v0;
 
-typedef struct
+typedef struct elf_internal_abiflags_v0
 {
   /* Version of flags structure.  */
   unsigned short version;