Rather than using a custom "Usage:", use the common cmd_usage() function,
and tail into it now that it returns 1 for us.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
        case 0:
        case 1:
        case 4:
-               printf("Usage:\n%s\n", cmdtp->usage);
-               return 1;
+               return cmd_usage(cmdtp);
 
        case 2:
                if (!strcmp(argv[1], "list")) {
                        printf("%d blocks written: %s\n",
                                n, (n == cnt) ? "OK" : "ERROR");
                        return (n == cnt) ? 0 : 1;
-               } else {
-                       printf("Usage:\n%s\n", cmdtp->usage);
-                       rc = 1;
-               }
+               } else
+                       rc = cmd_usage(cmdtp);
 
                return rc;
        }