gdb/riscv: Use TYPE_SAFE_NAME

In debug printing, use TYPE_SAFE_NAME instead of replicating the
functionality using TYPE_NAME and a null check.

gdb/ChangeLog:

	* riscv-tdep.c (riscv_print_arg_location): Use TYPE_SAFE_NAME.

gdb/ChangeLog

@@ -1,3 +1,7 @@
+2018-07-10  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* riscv-tdep.c (riscv_print_arg_location): Use TYPE_SAFE_NAME.
+
 2018-07-09  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* remote.c (show_hardware_watchpoint_limit): New function.

gdb/riscv-tdep.c

@@ -1939,12 +1939,8 @@ riscv_print_arg_location (ui_file *stream, struct gdbarch *gdbarch,
 			  struct riscv_arg_info *info,
 			  CORE_ADDR sp_refs, CORE_ADDR sp_args)
 {
-  const char* type_name = TYPE_NAME (info->type);
-  if (type_name == nullptr)
-    type_name = "???";
-
   fprintf_unfiltered (stream, "type: '%s', length: 0x%x, alignment: 0x%x",
-		      type_name, info->length, info->align);
+		      TYPE_SAFE_NAME (info->type), info->length, info->align);
   switch (info->argloc[0].loc_type)
     {
     case riscv_arg_info::location::in_reg: