[Why & How]
Add read backlight interface to get ABM data.
Signed-off-by: NYongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: NAnthony Koo <Anthony.Koo@amd.com>
Acked-by: NRodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>