etnaviv: Update headers from rnndb
The rnndb change (which is not in master yet as I wait for feedback on this) helps the understanding a bit when MSAA for GC3000 lands. The rnndb change can be found here https://github.com/austriancoder/etna_viv/commit/b721fced93eae9b54eda1d26b4d1a22011abff8e
I will push the rnndb change to master if this change is ready to land.