msm: ipa: add common internal header

Add a common internal header for ipa_v2 and ipa_v3.
Common definitions should go to this header.

CRs-Fixed: 995821
Change-Id: I39539cf661d9e0e0bb59236c92b169d3054485a9
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>