[Why]
The change of setting a timer callback on boot for 10 seconds is still
working, just lacked power down for DCN10.

[How]
Added power down for DCN10.
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: NAnthony Koo <Anthony.Koo@amd.com>
Acked-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: NDerek Lai <Derek.Lai@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>