m68k: Fix compiler warning (fprintf format string)

When argument checking is enabled, gcc throws this error:

error: format not a string literal and no format arguments

The patch rewrites the statement to satisfy the compiler.
It also removes a type cast which is not needed.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

m68k-dis.c

@@ -1104,7 +1104,7 @@ print_insn_arg (const char *d,
       {
         static const char *const cacheFieldName[] = { "nc", "dc", "ic", "bc" };
         val = fetch_arg (buffer, place, 2, info);
-        (*info->fprintf_func) (info->stream, cacheFieldName[val]);
+        (*info->fprintf_func) (info->stream, "%s", cacheFieldName[val]);
         break;
       }
 
@@ -1199,7 +1199,7 @@ print_insn_arg (const char *d,
 	{
 	  static const char *const scalefactor_name[] = { "<<", ">>" };
 	  val = fetch_arg (buffer, place, 1, info);
-	  (*info->fprintf_func) (info->stream, scalefactor_name[val]);
+	  (*info->fprintf_func) (info->stream, "%s", scalefactor_name[val]);
 	}
       else
 	{
@@ -1804,7 +1804,7 @@ match_insn_m68k (bfd_vma memaddr,
 
   save_p = p;
   info->print_address_func = dummy_print_address;
-  info->fprintf_func = (fprintf_ftype) dummy_printer;
+  info->fprintf_func = dummy_printer;
 
   /* We scan the operands twice.  The first time we don't print anything,
      but look for errors.  */