fm: Set lib_running variable only on cleanup

On SSR, we receive HW_ERR_EVENT,we set lib_running variable to 0.
Because of this, hci tx and monitor thread exits before cleanup or exit
happens, causing RX thread to be blocked on cond_wait and failure
happens.
Hence not setting variable during event read.

Change-Id: I82891e12c83fe5d06dbfec060d1ace1231fc25fd