drm/amd/display: Fix distribution of segments for PQ

For PQ case, redistribution of segments should be done differently
for FP16 case in order to handle content above FP16 value of 1.0

Signed-off-by: Anthony Koo <anthony.koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>