hal: gef: update gef extn to deinit gef library on hal deinit

Update gef extension to call deinit of gef library if the call is
available, so that gef is aware of audio hal state and gef init/deinit
is not tightly coupled with hal init/deinit.

Change-Id: I72ced9d6b9535563ee0b8e6d81efd634fcdc3ee3