drm/amdgpu: Fix xGMI access P2P mapping failure on GFXIP 9.4.3

On GFXIP 9.4.3, we dont need to rely on xGMI hive info to determine P2P
access.

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-and-tested-by: Mukul Joshi <mukul.joshi@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>