nvagetbios: Add generic checksignature()
nvagetbios: Add generic checksignature()

Add a generic function to check for both 0x55/0xaa
an 'PCIR', as a valid signature

Signed-off-by: Emil Velikov <1b0b652fb4718f95370964eb9b4e2b99538e5222@gmail.com>

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