panfrost: Drop NXR format

It's not clear this was ever exposed under any GL/DX/CL/VK/... extension
whatsoever...

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6326>
1 file changed