panfrost: Relax image check

Shader images on Valhall don't allow nonzero "Minimum level". However,
pan_texture lowers away nonzero minimum levels anyway, so there's nothing to
check. Fixes:

KHR-GLES31.core.shader_image_load_store.advanced-allMips-cs

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <!16315>
47 jobs for !16315 with relax in 16 minutes and 59 seconds (queued for 6 seconds)
latest merge request