qcacld-3.0: completion_freeq_lock needs initialization
Initialization of completion_freeq_lock was removed as part of
removing the completion thread. The lock still protects the
variable num_sends_allowed for copy engines used for sending.
Change-Id: Ia52d2c1b839d2ccfedbd175f1b8f60f953d08203
CRs-Fixed: 951563