Driver needs to send the ack message when it receives the
AC/DC interrupt from the SMU.

TODO: verify the client and src ids.

Bug: https://gitlab.freedesktop.org/drm/amd/issues/1043Reviewed-by: NEvan Quan <evan.quan@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>