freedreno: don't try to shadow layered textures

We will only hit this with multi-planar YUV external images, so we would
probably never hit this code path in the first place.  But if we did, it
wouldn't do the right thing so just bail.

Signed-off-by: Rob Clark <robdclark@gmail.com>

src/gallium/drivers/freedreno/freedreno_resource.c

@@ -133,6 +133,9 @@ fd_try_shadow_resource(struct fd_context *ctx, struct fd_resource *rsc,
 	struct pipe_resource *prsc = &rsc->base.b;
 	bool fallback = false;
 
+	if (prsc->next)
+		return false;
+
 	/* TODO: somehow munge dimensions and format to copy unsupported
 	 * render target format to something that is supported?
 	 */