backend/drm: drop wlr_drm_layer.pending_{width,height}

No need to store this info in struct wlr_drm_layer. We can just
extract the size when we need it.

backend/drm/drm.c

@@ -564,11 +564,8 @@ static bool drm_connector_set_pending_layer_fbs(struct wlr_drm_connector *conn,
 		}
 
 		if (layer_state->buffer != NULL) {
-			layer->pending_width = layer_state->buffer->width;
-			layer->pending_height = layer_state->buffer->height;
 			drm_fb_import(&layer->pending_fb, drm, layer_state->buffer, NULL);
 		} else {
-			layer->pending_width = layer->pending_height = 0;
 			drm_fb_clear(&layer->pending_fb);
 		}
 	}

backend/drm/libliftoff.c

@@ -177,6 +177,12 @@ static bool set_layer_props(struct wlr_drm_backend *drm,
 		const struct wlr_output_layer_state *state, uint64_t zpos) {
 	struct wlr_drm_layer *layer = get_drm_layer(drm, state->layer);
 
+	uint32_t width = 0, height = 0;
+	if (state->buffer != NULL) {
+		width = state->buffer->width;
+		height = state->buffer->height;
+	}
+
 	struct wlr_drm_fb *fb = layer->pending_fb;
 	int ret = 0;
 	if (state->buffer == NULL) {
@@ -190,9 +196,6 @@ static bool set_layer_props(struct wlr_drm_backend *drm,
 		return false;
 	}
 
-	uint32_t width = layer->pending_width;
-	uint32_t height = layer->pending_height;
-
 	uint64_t crtc_x = (uint64_t)state->x;
 	uint64_t crtc_y = (uint64_t)state->y;
 	uint64_t crtc_w = (uint64_t)width;

include/backend/drm/drm.h

@@ -50,8 +50,6 @@ struct wlr_drm_layer {
 	/* Buffer currently displayed on screen */
 	struct wlr_drm_fb *current_fb;
 
-	int pending_width, pending_height;
-
 	// One entry per wlr_drm_backend.planes
 	bool *candidate_planes;
 };