msm: ipa3: aggregate transfers completions

In order to reduce MIPS, program GSI in such a way that transfer
completions will be aggregated to a single event. Once IPA driver receives
the single completion event it will process all pending packets up to this
point.

Change-Id: Iec7e7e13048e6c4abc9ce71bc65773ac07502587
CRs-Fixed: 2022853
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>