gf100: Add POST_DEPTH_COVERAGE register to database
gf100: Add POST_DEPTH_COVERAGE register to database

Found with the trace from https://trello.com/c/kuMPh88f , verified
working in WIP for ARB_post_depth_coverage implementation:

https://github.com/Lyude/mesa/tree/wip/gm200-ARB_post_depth_coverage

Signed-off-by: Lyude <1d05c5face2dc786c0af2cf362656a51f0df9b63@redhat.com>

envytools/envytools,karolherbst/envytools,pierremoreau/envytools,envytools/envytools,karolherbst/envytools,karolherbst/envytools,envytools/envytools,envytools/envytools,karolherbst/envytools,pierremoreau/envytools,karolherbst/envytools,pierremoreau/envytools,envytools/envytools,pierremoreau/envytools,pierremoreau/envytools