qcacmn: Optimize congestion calculation logic

In current code logic, in case of channel utilization value is 0, 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: Iff030cf4a682d6e585d6f812a522cb8b6683cc44
CRs-Fixed: 2812978