gta4xl-common: Add feature flag for FEATURE_IPSEC_TUNNELS

This commit adds the IPSEC_TUNNELS feature flag, with XFRM Interfaces
used as the implementation of choice.

Bug: 117183273
Bug: 137629222
Test: Compiles, passes tunnel-mode CTS tests
Test: adb shell pm list features
Change-Id: I19c598947525783850b29d149db85db89f8b347e
diff --git a/common.mk b/common.mk
index 4e50f52..798ba49 100644
--- a/common.mk
+++ b/common.mk
@@ -198,6 +198,7 @@
     frameworks/native/data/etc/android.software.app_widgets.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.app_widgets.xml \
     frameworks/native/data/etc/android.software.device_id_attestation.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.device_id_attestation.xml \
     frameworks/native/data/etc/android.software.freeform_window_management.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.freeform_window_management.xml \
+    frameworks/native/data/etc/android.software.ipsec_tunnels.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.ipsec_tunnels.xml \
     frameworks/native/data/etc/android.software.midi.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.midi.xml \
     frameworks/native/data/etc/android.software.opengles.deqp.level-2020-03-01.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.opengles.deqp.level.xml \
     frameworks/native/data/etc/android.software.picture_in_picture.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.software.picture_in_picture.xml \