drm/amd/pm: Do not support swSMU if SMU IP is disabled

When SMU IP is disabled by ip_block_mask, driver
should not refer to any dpm/swSMU callback. Instead,
any driver call into swSMU/dpm callback needs to
return error code EOPNOTSUPP.

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>