drm/amd/display: Modify ABM 2.2 Max Reduction

[Why]
Reduced backlight for ABM 2.2 at levels 1 and 2 is desired for
power savings.

[How]
Reduce the max reduction parameters for ABM 2.2

Signed-off-by: Josip Pavic <Josip.Pavic@amd.com>
Reviewed-by: Josip Pavic <Josip.Pavic@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>