drm/amd/display: Check for sharpening case when calculating max vtaps for scaler

drm/amd/display: Check for sharpening case when calculating max vtaps for scaler

[Why & How]
- calc_lb_num_partitions has check when scaler is not enabled to use
 larger LB in calculations for max vtaps based on viewport being 1:1
- however, scaler is forced on when sharpening is enabled, so need
 to consider this in check
- taps is predetermined in spl_get_optimal_number_of_taps prior to
 calc_lb_num_partitions.  Add check for taps not 1 to handle
 sharpening case

Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Samson Tam <Samson.Tam@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>