Add 3 sub flags to notify guest for indirect reg access of
gc, mmhub and ih

The host sets these flags depending on L1 RAP version,
asic and other scenarios. These flags ensure that
there is compatibility between different guest/host/vbios versions.
Signed-off-by: NRohit Khaire <rohit.khaire@amd.com>
Reviewed-by: NMonk Liu <monk.liu@amd.com>
Acked-by: NAlex Deucher <alexander.deucher@amd.com>
Acked-by: NLuben Tuikov <luben.tuikov@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>