disas/microblaze: Fix warnings caused by missing 'static' attribute

Warnings from the Sparse static analysis tool:

disas/microblaze.c:289:3: warning:
 symbol 'opcodes' was not declared. Should it be static?
disas/microblaze.c:570:6: warning:
 symbol 'register_prefix' was not declared. Should it be static?
disas/microblaze.c:571:6: warning:
 symbol 'special_register_prefix' was not declared. Should it be static?
disas/microblaze.c:572:6: warning:
 symbol 'fsl_register_prefix' was not declared. Should it be static?
disas/microblaze.c:573:6: warning:
 symbol 'pvr_register_prefix' was not declared. Should it be static?

Remove the unused variable special_register_prefix.
The variable pvr_register_prefix was unused, too, but can be used.
Add also 'const' where possible.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

disas/microblaze.c

@@ -275,7 +275,7 @@ enum microblaze_instr_type {
 
 #define MAX_OPCODES 280
 
-struct op_code_struct {
+static struct op_code_struct {
   const char *name;
   short inst_type; /* registers and immediate values involved */
   short inst_offset_type; /* immediate vals offset from PC? (= 1 for branches) */
@@ -567,10 +567,9 @@ struct op_code_struct {
 };
 
 /* prefix for register names */
-char register_prefix[] = "r";
-char special_register_prefix[] = "spr";
-char fsl_register_prefix[] = "rfsl";
-char pvr_register_prefix[] = "rpvr";
+static const char register_prefix[] = "r";
+static const char fsl_register_prefix[] = "rfsl";
+static const char pvr_register_prefix[] = "rpvr";
 
 
 /* #defines for valid immediate range */
@@ -738,7 +737,9 @@ get_field_special (long instr, struct op_code_struct * op)
    default :
      {
        if ( ((((instr & IMM_MASK) >> IMM_LOW) ^ op->immval_mask) & 0xE000) == REG_PVR_MASK) {
-	 sprintf(tmpstr, "%spvr%d", register_prefix, (unsigned short)(((instr & IMM_MASK) >> IMM_LOW) ^ op->immval_mask) ^ REG_PVR_MASK);
+	  sprintf(tmpstr, "%s%u", pvr_register_prefix,
+                 (unsigned short)(((instr & IMM_MASK) >> IMM_LOW) ^
+                                  op->immval_mask) ^ REG_PVR_MASK);
 	 return(strdup(tmpstr));
        } else {
 	 strcpy(spr, "pc");