drm/amdkfd: report atomics support in io_links over xgmi

Link atomics support over xGMI should be reported independently of PCIe.
Do not set NO_ATOMICS flags on devices that support xGMI but that do not
have atomics support over PCIe.

Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Tested-by: Ramesh Errabolu <ramesh.errabolu@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>