msm: ipa4: add multi PDN support

IPAv4 presents multi PDN support. This change provides backward
compatibility towards user space and allows setting NAT rules
for several PDNs. Metadata replacement is also supported as part
of this feature.

CRs-Fixed: 2040674
Change-Id: If0ee3cb1da5b40a4d0887aaec276e5b78e947337
Signed-off-by: Amir Levy <alevy@codeaurora.org>