panfrost: Simplify depth/stencil/alpha

The alpha test is lowered by the frontend so we can drop that unused
code path, and stencil state can be computed at CSO create time to
reduce draw-time complexity.

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/6195>
10 files changed