drm/amd/display: Calculate MALL cache lines based on Mblks required

[Description]
- Calculation for NumWays in MALL should be based on
number of MBlks

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alvin Lee <Alvin.Lee2@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>