AMD VBIOS option ROMs often modify themselves during initialization.
Check for the presence of a VBIOS at 0xc0000 before populating the
VFCT table. If a matching ROM is found, use it for the source of
the copy.
Tested on Gardenia (Stoney) variant by observing amdgpu driver's
dmesg output.
Change-Id: I5be7e1562bde51800c5b0e704c79812d85bcf362
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/19383
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
6f978cfd1a