panfrost: Implement provoking vertices on Valhall

Starting with Valhall, the provoking vertex state is specified per-framebuffer
(batch) instead of per-draw. We use the pan_tristate infrastructure to translate
between desktop OpenGL's per-draw semantics to Valhall's per-framebuffer
semantic. This is notably not required for GLES or Vulkan.

If the provoking vertex is unset when the tiler context is generated, it could
be set (incompatibly) later in the batch, and the tiler context's provoking
vertex field would no longer match the framebuffer's. That would violate a
hardware invariant. To ensure that doesn't happen, we make sure to set provoking
vertexes *before* generating the tiler context so it can't change after.

Fixes arb-provoking-vertex-render on Valhall.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Part-of: <!17068>
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