Stop checking wlr_output_attach_buffer return value

Update for [1]. Everything is now checked at commit-time.

[1]: https://github.com/swaywm/wlroots/pull/2097

sway/desktop/output.c

@@ -504,9 +504,7 @@ static bool scan_out_fullscreen_view(struct sway_output *output,
 	wlr_presentation_surface_sampled_on_output(server.presentation, surface,
 		wlr_output);
 
-	if (!wlr_output_attach_buffer(wlr_output, &surface->buffer->base)) {
-		return false;
-	}
+	wlr_output_attach_buffer(wlr_output, &surface->buffer->base);
 	return wlr_output_commit(wlr_output);
 }