qcacmn: Optimize congestion score calculation

In current code logic, in case of channel utilization value less
than 3, the congestion value treated as “not present” and give
it a medium score. This will cause a very clean channel get a medium
score.

To fix the issue, need calculated congestion score from 1-100 and
not 0-100.

Change-Id: I6abb257e8298e4db3104fdc20351bbadaa7c2ec5
CRs-Fixed: 2812978