qcacmn: Add support for adaptive dwell scan time

Dwell time can be modify based on channel congestion per scan
request.
Add changes to enable firmware to use scan control flag and select
dwell time optimization algorithm based on ini values.

Change-Id: Iea3de57c1b7d087442e4b8984b4184d24bb8c930
CRs-Fixed: 994443
3 files changed