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>
diff --git a/common/cmd_misc.c b/common/cmd_misc.c
index 8439da2..061b1bb 100644
--- a/common/cmd_misc.c
+++ b/common/cmd_misc.c
@@ -32,17 +32,15 @@
 	ulong start = get_timer(0);
 	ulong delay;
 
-	if (argc != 2) {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	if (argc != 2)
+		return cmd_usage(cmdtp);
 
 	delay = simple_strtoul(argv[1], NULL, 10) * CONFIG_SYS_HZ;
 
 	while (get_timer(start) < delay) {
-		if (ctrlc ()) {
+		if (ctrlc ())
 			return (-1);
-		}
+
 		udelay (100);
 	}