Mali GPUs support Z24_UNORM stored on three bytes instead of four. Add a new format for this case. Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Eric R. Smith <eric.smith@collabora.com> Reviewed-by: Christoph Pillmayer <christoph.pillmayer@arm.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37158>