drm/amd/display: Disable ABM before destroy ABM struct

[Why]
When disable driver, OS will set backlight optimization
then do stop device.  But this flag will cause driver to
enable ABM when driver disabled.

[How]
Send ABM disable command before destroy ABM construct

Signed-off-by: Paul Hsieh <paul.hsieh@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>