nvbios: check for bios->conn.entries array before using it
nvbios: check for bios->conn.entries array before using it

encountered on the second vbios on a GTX 690

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