Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

board/mpl/common/common_util.c

@@ -559,7 +559,7 @@ int do_mplcommon(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 		return 0;
 	}
 #endif
-	printf("Usage:\n%s\n", cmdtp->usage);
+	cmd_usage(cmdtp);
 	return 1;
 }