panfrost: Adjust the format for AFBC textures on Bifrost v7

panfrost: Adjust the format for AFBC textures on Bifrost v7

On Bifrost v7, AFBC textures can't be used with a non-identity component
order. Let's patch the format so the component order is always RGB[A].
That means we're lying about the internal format, but that shouldn't be
a problem as long as we don't share the resource.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8125>