disas/i386: Avoid NULL pointer dereference in error case

In a code path where we hit an internal disassembler error, execution
would subsequently attempt to dereference a NULL pointer.  This
should never happen, but avoid the crash.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 1488556233-31246-3-git-send-email-peter.maydell@linaro.org

disas/i386.c

@@ -4043,7 +4043,7 @@ print_insn (bfd_vma pc, disassemble_info *info)
 	    }
 	}
 
-      if (putop (dp->name, sizeflag) == 0)
+      if (dp->name != NULL && putop (dp->name, sizeflag) == 0)
         {
 	  for (i = 0; i < MAX_OPERANDS; ++i)
 	    {