nv17: Add zclear registers(from renouveau)
nv17: Add zclear registers(from renouveau)

grate-driver/envytools,kfractal/envytools,MoochMcGee/envytools,karolherbst/envytools,karolherbst/envytools,grate-driver/envytools,karolherbst/envytools,MoochMcGee/envytools,MoochMcGee/envytools,kfractal/envytools,grate-driver/envytools,hakzsam/envytools,pierremoreau/envytools,MoochMcGee/envytools,hakzsam/envytools,karolherbst/envytools,envytools/envytools,grate-driver/envytools,karolherbst/envytools,hakzsam/envytools,pierremoreau/envytools,envytools/envytools,envytools/envytools,hakzsam/envytools,kfractal/envytools,kfractal/envytools,pierremoreau/envytools,pierremoreau/envytools,hakzsam/envytools,kfractal/envytools,envytools/envytools,grate-driver/envytools,envytools/envytools,pierremoreau/envytools,MoochMcGee/envytools