Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/common/cmd_fdc.c b/common/cmd_fdc.c
index d995ff2..c6265c3 100644
--- a/common/cmd_fdc.c
+++ b/common/cmd_fdc.c
@@ -801,7 +801,7 @@
 		boot_drive=simple_strtoul(argv[2], NULL, 10);
 		break;
 	default:
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 	/* setup FDC and scan for drives  */