panfrost: mmap error-handling
Here's a bit of yak-shaving for allocation / mmap error handling in Panfrost.
Unfortunately, most of the allocations here happens during the p_context::draw_vbo
or other functions that doesn't allow us to return a pipe_error
to report the OOM situation to the client API. So instead we try as hard as we can to avoid crashing, and report an error when it's feasible.
This contains most of the patches from !32143, but without overly hacky patches for now.