msm: ipa: add wakelock to IPA PM

Hold a wakelock as long as an APPS clinent is activated from IPA PM.
This will ensure that wakelock is held during TX operation to IPA.

Change-Id: I71c921d7a17c6eed85cf36c0855b72faaf0b3c4c
CRs-Fixed: 2179218
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>