drm/amd/powerplay: update vce power gate state for baffin.

Forgot to save the current gate state so we don't know
what the current state is if we try and gate/ungate the
block.

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>