msm: ipa3: SRAM NAT, DDR NAT, back-and-forth NAT

A new application level feature has NAT running out of SRAM, DDR,
or both. The addtion of just this feature's header to the kernel will
allow it to be propagated to older kernels, such that they can be
compatible (in terms of structure size) with the new application level
feature.

Change-Id: I16b5bfaa1156c69e0a6ae0c2ca4be416a283d049
CRs-Fixed: 2437567
Signed-off-by: Perry Randise <prandise@codeaurora.org>