drm/amdgpu: remove program of lbpw for renoir

These is no LBPW on Renoir. So removing program of lbpw for renoir.

Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>