drm/amdgpu: skip reroute ih for some ASICs

Add check before reroute ih setting, it's not supported by some ASICs.

Signed-off-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>