cpukit riscv: Address unused parameter warnings

Add "(void) param;" annotation to address unused parameter warnings.
Found with GCC's warning -Wunused-parameter.

cpukit/libdl/rtl-mdreloc-riscv.c

@@ -52,6 +52,9 @@
 uint32_t
 rtems_rtl_elf_section_flags (const rtems_rtl_obj* obj,
                              const Elf_Shdr*      shdr) {
+  (void) obj;
+  (void) shdr;
+
   return 0;
 }
 
@@ -86,6 +89,8 @@ rtems_rtl_elf_arch_section_free (const rtems_rtl_obj* obj,
 
 bool
 rtems_rtl_elf_rel_resolve_sym (Elf_Word type) {
+  (void) type;
+
   return true;
 }
 
@@ -160,6 +165,8 @@ rtems_rtl_elf_reloc_rela (rtems_rtl_obj*      obj,
                           const Elf_Byte            syminfo,
                           const Elf_Word            symvalue,
                           const bool parsing) {
+  (void) symname;
+
   Elf_Addr *where;
 
   char bits = (sizeof(Elf_Word) * 8);
@@ -415,6 +422,13 @@ rtems_rtl_elf_relocate_rel (rtems_rtl_obj*      obj,
                             const char*               symname,
                             const Elf_Byte            syminfo,
                             const Elf_Word            symvalue) {
+  (void) obj;
+  (void) rel;
+  (void) sect;
+  (void) symname;
+  (void) syminfo;
+  (void) symvalue;
+
   rtems_rtl_set_error (EINVAL, "rel type record not supported");
   return rtems_rtl_elf_rel_failure;
 }

cpukit/score/cpu/riscv/cpu.c

@@ -192,6 +192,8 @@ uint32_t _CPU_ISR_Get_level( void )
 
 void *_CPU_Thread_Idle_body( uintptr_t ignored )
 {
+  (void) ignored;
+
   while ( true ) {
     __asm__ volatile ( "wfi" );
   }

cpukit/score/cpu/riscv/riscv-context-initialize.c

@@ -47,6 +47,9 @@ void _CPU_Context_Initialize(
   void            *tls_area
 )
 {
+  (void) new_level;
+  (void) is_fp;
+
   void *stack;
 
   stack = _Addresses_Add_offset( stack_area_begin, stack_area_size );