aco: add new NOP insertion pass for GFX6-9

This new pass is more similar to the GFX10 pass and should be able to
handle control flow better.

No pipeline-db changes.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4004>
2 files changed