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_sata.c b/common/cmd_sata.c
index 7be58e5..7efa859 100644
--- a/common/cmd_sata.c
+++ b/common/cmd_sata.c
@@ -77,8 +77,7 @@
 	switch (argc) {
 	case 0:
 	case 1:
-		cmd_usage(cmdtp);
-		return 1;
+		return cmd_usage(cmdtp);
 	case 2:
 		if (strncmp(argv[1],"inf", 3) == 0) {
 			int i;
@@ -115,8 +114,7 @@
 			}
 			return rc;
 		}
-		cmd_usage(cmdtp);
-		return 1;
+		return cmd_usage(cmdtp);
 	case 3:
 		if (strncmp(argv[1], "dev", 3) == 0) {
 			int dev = (int)simple_strtoul(argv[2], NULL, 10);
@@ -147,8 +145,7 @@
 			}
 			return rc;
 		}
-		cmd_usage(cmdtp);
-		return 1;
+		return cmd_usage(cmdtp);
 
 	default: /* at least 4 args */
 		if (strcmp(argv[1], "read") == 0) {
@@ -184,8 +181,7 @@
 				n, (n == cnt) ? "OK" : "ERROR");
 			return (n == cnt) ? 0 : 1;
 		} else {
-			cmd_usage(cmdtp);
-			rc = 1;
+			return cmd_usage(cmdtp);
 		}
 
 		return rc;