Address review feedback

rootston/layer_shell.c

@@ -198,13 +198,11 @@ void arrange_layers(struct roots_output *output) {
 		ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY,
 		ZWLR_LAYER_SHELL_V1_LAYER_TOP,
 	};
+	size_t nlayers = sizeof(layers_above_shell) / sizeof(layers_above_shell[0]);
 	struct roots_layer_surface *layer, *topmost = NULL;
-	for (size_t i = 0;
-			i < sizeof(layers_above_shell) / sizeof(layers_above_shell[0]);
-			++i) {
+	for (size_t i = 0; i < nlayers; ++i) {
 		wl_list_for_each_reverse(layer,
-				&output->layers[layers_above_shell[i]],
-				link) {
+				&output->layers[layers_above_shell[i]], link) {
 			if (layer->layer_surface->current.keyboard_interactive) {
 				topmost = layer;
 				break;