Turns model based reverse updates on for coefficients in an
effort to reduce the memory requirement for counters.

With this patch the counters needed will be reduced by about
75% since only 3 counts are needed instead of 12.

The impact in performance is:
derf300: -0.252%
stdhd250: -0.046%

However retraining should alleviate some of the drop in
performance.

Change-Id: I6f2b3e13f6d5520aa3400b0b228fb5e8b4a43caa