drm/amdgpu: Use SKU instead of DID for FRU check v2

The VG20 DIDs 66a0, 66a1 and 66a4 are used for various SKUs that may or may
not have the FRU EEPROM on it. Parse the VBIOS to check for server SKU
variants (D131 or D134) until a more general solution can be determined.

v2: Remove string-based logic, correct the VBIOS string comment

Signed-off-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>