Remember if direct scanout fails

If a view fails direct scanout, we remember if it fails so we don't
bother trying again. This removes a lot of log spam of the atomic DRM
test failing in this case.

include/sway/tree/view.h

@@ -75,6 +75,7 @@ struct sway_view {
 	char *title_format;
 
 	bool using_csd;
+	bool failed_scan_out;
 
 	struct timespec urgent;
 	bool allow_request_urgent;