output/cursor: fix buffer size when nested and scaled

The Wayland, X11 and headless backends don't really care about the
cursor size. We were picking a size identical to the texture size
in that case. This is incorrect for LoDPI cursor textures on HiDPI
outputs: in that case, we need to scale up the cursor texture.

Fixes the cursor being chopped off under the Wayland backend with
scale > 1.

types/output/cursor.c

@@ -303,8 +303,8 @@ static struct wlr_buffer *render_cursor_buffer(struct wlr_output_cursor *cursor)
 	struct wlr_renderer *renderer = output->renderer;
 	assert(allocator != NULL && renderer != NULL);
 
-	int width = texture->width;
+	int width = texture->width * output->scale / scale;
-	int height = texture->height;
+	int height = texture->height * output->scale / scale;
 	if (output->impl->get_cursor_size) {
 		// Apply hardware limitations on buffer size
 		output->impl->get_cursor_size(cursor->output, &width, &height);