Enable ip6table_nat as module for x86 and arm

Set kernel config CONFIG_IP6_NF_NAT to "m".

BUG=b/184087614
TEST=Presubmit and manually verify config set in image
RELEASE_NOTE=Enable ip6table_nat as module

Change-Id: I5e18d03c22a88ab950a53478cb80b07e95bf2f94
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/15476
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
3 files changed