freedreno/a6xx: convert blend state to stateobj

And move to new register builders while we are at it.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3565>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3565>
5 files changed