frontend/nine: Fix ATOC handling
The previous code was incorrectly checking the previous value of alphatestenable. In addition, remove an optimization that cannot hit (as we filter out redundant state settings). cc: mesa-stable Fixes: 1272640d ("st/nine: Fix alpha to coverage states") Signed-off-by:Axel Davy <davyaxel0@gmail.com> Acked-by:
David Heidelberg <david.heidelberg@collabora.com> Part-of: <mesa/mesa!18021> (cherry picked from commit 4f953ad5)