msm: ipa: fix for wakelock refcnt

When IPA driver votes for IPA power collapse it first checks if
channels are empty. In case that the channels are not empty,
a wakelock needs to be acquired before starting to process the packets.

Change-Id: Ib4d5942e374efc4ceb195e6ccdc446ed8a06aeb0
CRs-Fixed: 2031601
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>