drm/amd/pm: remove some useless code for vangogh

This patch is to remove some useless code for vangogh.
In the earlier code, vangogh can't finish all the sequence of
smu late init. But now vangogh has one stable work state,so
remove the useless code.

Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Acked-by: Xiaomeng Hou <Xiaomeng.Hou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>