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_scsi.c b/common/cmd_scsi.c
index 5b2df28..6b937f9 100644
--- a/common/cmd_scsi.c
+++ b/common/cmd_scsi.c
@@ -229,8 +229,7 @@
 		boot_device = argv[2];
 		break;
 	default:
-		cmd_usage(cmdtp);
-		return 1;
+		return cmd_usage(cmdtp);
 	}
 
 	if (!boot_device) {
@@ -346,7 +345,8 @@
 {
 	switch (argc) {
     case 0:
-    case 1:	cmd_usage(cmdtp);	return 1;
+    case 1:	return cmd_usage(cmdtp);
+
     case 2:
 			if (strncmp(argv[1],"res",3) == 0) {
 				printf("\nReset SCSI\n");
@@ -392,8 +392,7 @@
 					printf("\nno SCSI devices available\n");
 				return 1;
 			}
-			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);
@@ -421,8 +420,7 @@
 				}
 				return 1;
 			}
-			cmd_usage(cmdtp);
-			return 1;
+			return cmd_usage(cmdtp);
     default:
 			/* at least 4 args */
 			if (strcmp(argv[1],"read") == 0) {
@@ -437,8 +435,7 @@
 				return 0;
 			}
 	} /* switch */
-	cmd_usage(cmdtp);
-	return 1;
+	return cmd_usage(cmdtp);
 }
 
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