Adapt strength of AQ2.
Adapt the use of segmentation in AQ mode 2 based on the ambient kf/arf/gf Q. Disable segmentation where the rate per SB is very low and overheads are likely to outweigh the benefits. This patch reduces the -ve average metrics impact of AQ mode 2 while allowing stronger 3 segment AQ in some cases. Average improvement ~0.5-1.0%. Change-Id: I5892dfcc7507c5cc6444531cc7fe17554cf8d0c7