panfrost: XMLify Bifrost preload
There's a lot of code here since the meaning of this field changes
depending on shader state. The good news is that our careful handling
allows preload registers to be decoded now, which pandecode could not
previously do. Likewise, the cmdstream code to emit this is now much
more obvious.
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/6440>