LRWD: add time based logic to re-enable Watchdog

After Watchdog has triggered once and still fail to connect,
Watchdog will not be allowed to work in 2 hours. Nevertheless,
Watchdog could be allowed immediately if device enter connected
state.

Bug: 123349476
Test: Manually test
      check Watchdog won't be allowed after network un-blacklisted
Test: frameworks/opt/net/wifi/tests/wifitests/runtests.sh

Change-Id: I4137a9add6d9b8fba17473ac5398075682c12469
2 files changed