drm/amdgpu: also print the pci revision when printing the pci ids

The driver makes use of this information so print if to aid in
debugging.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Samuel Li <samuel.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>