panfrost: Fix precise occlusion queries on Bifrost

Bifrost doesn't need the sample count to be divided by four for
non-MSAA framebuffers.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <!8172>
42 jobs for !8172 with bf-occlude in 11 minutes and 2 seconds (queued for 4 seconds)
merge request