panfrost: Draw the wallpaper when only depth/stencil bufs are cleared

panfrost: Draw the wallpaper when only depth/stencil bufs are cleared

When only the depth/stencil bufs are cleared, we should make sure the
color content is reloaded into the tile buffers if we want to preserve
their content.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>