Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/mpl/common/common_util.c b/board/mpl/common/common_util.c
index 877a2d0..d169391 100644
--- a/board/mpl/common/common_util.c
+++ b/board/mpl/common/common_util.c
@@ -559,7 +559,7 @@
 		return 0;
 	}
 #endif
-	printf("Usage:\n%s\n", cmdtp->usage);
+	cmd_usage(cmdtp);
 	return 1;
 }