ANDROID: GKI: Convert L2TP as modules

Converts L2TP and PPP over L2TP as GKI modules.
CONFIG_L2TP: Layer Two Tunneling Protocol (L2TP)
CONFIG_PPOL2TP: PPP over L2TP

Makes CONFIG_NETFILTER_XT_MATCH_L2TP visible in the savedefconfig.

Bug: 232431151
Test: TH
Change-Id: I0e1cbd8f04f97f172f8b1551eade21cf303b24ed
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
diff --git a/modules.bzl b/modules.bzl
index bee7fc6..f6c68a1 100644
--- a/modules.bzl
+++ b/modules.bzl
@@ -31,6 +31,8 @@
     "net/ieee802154/6lowpan/ieee802154_6lowpan.ko",
     "net/ieee802154/ieee802154.ko",
     "net/ieee802154/ieee802154_socket.ko",
+    "net/l2tp/l2tp_core.ko",
+    "net/l2tp/l2tp_ppp.ko",
     "net/mac80211/mac80211.ko",
     "net/mac802154/mac802154.ko",
     "net/nfc/nfc.ko",