defconfig: arm64: msm: Enable support for IPv4 tethering

Commit 8993cf8e ("netfilter: move NAT Kconfig switches out of
the iptables scope") and 0bbe80e5 ("netfilter: masquerading needs
to be independent of x_tables in Kconfig") remove support for NAT and
masquerade from iptables and separate the functionality.

Add support for IPv4 tethering using the new configurations.

CRs-Fixed: 861867
Change-Id: Ie137eb7a540c2d493a9a63307d734e8ebbe84e9d
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>