pan/decode: Be robust to NULL texture payload

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Mary Guillemard <mary.guillemard@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29382>

src/panfrost/lib/genxml/decode.c

@@ -242,6 +242,9 @@ pandecode_texture_payload(struct pandecode_context *ctx, mali_ptr payload,
    unsigned nr_samples =
       tex->dimension == MALI_TEXTURE_DIMENSION_3D ? 1 : tex->sample_count;
 
+   if (!payload)
+      return;
+
    /* A bunch of bitmap pointers follow.
     * We work out the correct number,
     * based on the mipmap/cubemap