cmd_usage(): simplify return code handling

Lots of code use this construct:

	cmd_usage(cmdtp);
	return 1;

Change cmd_usage() let it return 1 - then we can replace all these
ocurrances by

	return cmd_usage(cmdtp);

This fixes a few places with incorrect return code handling, too.

Signed-off-by: Wolfgang Denk <wd@denx.de>

common/cmd_vfd.c

@@ -49,10 +49,8 @@ int do_vfd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	ulong bitmap;
 
-	if (argc != 2) {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	if (argc != 2)
+		return cmd_usage(cmdtp);
 
 	if (argv[1][0] == '/') {	/* select bitmap by number */
 		bitmap = simple_strtoul(argv[1]+1, NULL, 10);