Access the exported P2P dmabuf over XGMI, if available.
Otherwise, fall back to the existing PCIe method.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Arunpravin <apaneers@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>