gpu: nova-core: do not consider 0xBB77 as a valid PCI ROM header signature

gpu: nova-core: do not consider 0xBB77 as a valid PCI ROM header signature

Nvidia GPUs have some PCI expansion ROM sections that have an Nvidia-
specific signature instead of 0xAA55.  Signature 0xBB77 is actually an
internal-only value that has been deprecated for over a decade.
Nova-core will never encounter a GPU with that signature, so don't look
for it.

Signed-off-by: Timur Tabi <ttabi@nvidia.com>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260417191359.1307434-3-ttabi@nvidia.com
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>