Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index 9055672..68f1675 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -454,13 +454,13 @@
 	}
 	/* Unrecognized command */
 	else {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 
 	if (images.state >= state) {
 		printf ("Trying to execute a command out of order\n");
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}