For 11A only AP, HT and DS IE are not present in beacon,
STA may receive the beacon on adjacent channel, then
driver may record wrong channel frequency in scan entry.
Fix by update the channel frequency by old scan entry
channel frequency if new beacon RSSI lower than old beacon
RSSI and gap is bigger than 40 db within 5s.
Change-Id: Idbd144befa78597fcd50a753ca13b0f11d1f45f5
CRs-Fixed: 3484664
8859a74378