Based on the scan request flags from kernel, modify the
adaptive dwell time and DBS scan request policy.
In high accuracy mode, disable DBS scan and adaptive dwell
time scan mode.
In a low power/span mode, enable aggressive adaptive dwell time
and DBS scan to save power and time.
Change-Id: I23498799c05a252cbc9c9f6d50b847130dd0ceac
CRs-Fixed: 2197171