panfrost: Set .array_size on Bifrost

Fixes dEQP-GLES2.functional.texture.mipmap.cube.generate.rgba8888_nicest

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7408>
1 file changed