drm/amd/powerplay: fix copy error in powerplay.

v2: fix typos.

should disable led dpm feature when stop dpm.

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>