cansequence: exit with failure in case of unknown option

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

cansequence.c

@@ -281,7 +281,8 @@ int main(int argc, char **argv)
 			break;
 
 		default:
-			fprintf(stderr, "Unknown option %c\n", opt);
+			print_usage(basename(argv[0]));
+			exit(EXIT_FAILURE);
 			break;
 		}
 	}