gallivm: remove illegal and unused function attributes

READONLY is illegal on calls. Others were unused.

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20146>
Change-Id: Id27ac112e99615f5f8a13cf76d37161ebaae4362
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/mesa/+/969297
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>
Fuchsia-Auto-Submit: Josh Gargus <jjosh@google.com>
Reviewed-by: John Bauman <jbauman@google.com>
3 files changed