qcacmn: update average rssi in scan entry

If elapsed time since last rssi update for a particular
scan entry is smaller than a thresold, calculate a
running average of the RSSI values. Otherwise last RSSI
is more representive of the signal strength.

Change-Id: I4cbecc8b6bfbb73c272544114b063b25c26e14fe
CRs-Fixed: 1095299
4 files changed