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/board/spear/common/spr_misc.c b/board/spear/common/spr_misc.c
index d99036b..0562222 100644
--- a/board/spear/common/spr_misc.c
+++ b/board/spear/common/spr_misc.c
@@ -215,10 +215,8 @@
 	char *s, *e;
 	char i2c_mac[20];
 
-	if ((argc > 3) || (argc < 2)) {
-		cmd_usage(cmdtp);
-		return 1;
-	}
+	if ((argc > 3) || (argc < 2))
+		return cmd_usage(cmdtp);
 
 	if ((!strcmp(argv[1], "cpufreq")) || (!strcmp(argv[1], "ddrfreq"))) {
 
@@ -286,8 +284,7 @@
 		return 0;
 	}
 
-	cmd_usage(cmdtp);
-	return 1;
+	return cmd_usage(cmdtp);
 }
 
 U_BOOT_CMD(chip_config, 3, 1, do_chip_config,