Standardize command usage messages with cmd_usage()

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/common/cmd_bmp.c b/common/cmd_bmp.c
index bc08b26..e60f18b 100644
--- a/common/cmd_bmp.c
+++ b/common/cmd_bmp.c
@@ -120,7 +120,7 @@
 	        y = simple_strtoul(argv[4], NULL, 10);
 	        break;
 	default:
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 
@@ -132,7 +132,7 @@
 	} else if (strncmp(argv[1],"display",1) == 0) {
 	    return (bmp_display(addr, x, y));
 	} else {
-		printf ("Usage:\n%s\n", cmdtp->usage);
+		cmd_usage(cmdtp);
 		return 1;
 	}
 }