WIFI: Fix wifi auto-connect to other saved APs during WPS PIN scanning.

During WPS PIN scanning and AP side not enter the PIN, continuously
turn off/on screen will sometimes cause the phone auto-connect to
other saved APs.

WifiStateMachine accepts screenOn event, and sometimes will enable
all networks.

This change will NOT enable all networks in screenOn event While wps
is running.

Change-Id: I539ee6020a8e2b2fa6892c88569c302f89e8f5ed
CRs-Fixed: 646433