tinywl: init cursor_mode

valgrind complains on a use-before-init for the cursor mode.

tinywl/tinywl.c

@@ -842,6 +842,7 @@ int main(int argc, char *argv[]) {
 	 *
 	 * And more comments are sprinkled throughout the notify functions above.
 	 */
+	server.cursor_mode = TINYWL_CURSOR_PASSTHROUGH;
 	server.cursor_motion.notify = server_cursor_motion;
 	wl_signal_add(&server.cursor->events.motion, &server.cursor_motion);
 	server.cursor_motion_absolute.notify = server_cursor_motion_absolute;