This is a cherry-pick Change 91968 from GB branch.
Wakelock will get released while
1) no request pending to be sent out, in which mRequestMessagesPending increases
before calling EVENT_SEND and decreases while handling EVENT_SEND.
and
2) no waiting requests sent to RIL but no replied, in which mRequestMessagesWaiting
increases while sending request and decreases while handling response.
Both will be cleared while WAKE_LOCK_TIMEOUT occurs to recovery from out of sync situation.
bug: 3369427, 3370827
Change-Id: Ibbcc95d67a292ffe20339ea9bdb0f2e4a4988da0
4376538c47