CHROMIUM: arcvm: Enable XFRM_MIGRATE for x86

This patch enables for x86 the XFRM_MIGRATE option which is now
required on by Android VTS on Android 13. This option was already
enabled in the arm64 ARCVM config.

BUG=b:236908747
TEST=all vts_kernel_net_tests testMigrateXfrmIntf test cases now pass.
(chroot) $ cros_workon --board=${BOARD} start arcvm-kernel-ack-5_10
(chroot) $ emerge-$BOARD arcvm-kernel-ack-5_10
(chroot) $ cros deploy <dut_ip> arcvm-kernel-ack-5_10
(tm-dev lunch terminal) $ atest vts_kernel_net_tests

Change-Id: I0d204cd3acb2827f2739231880a8d751296ab1ee
Signed-off-by: Hugo Benichi <hugobenichi@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/3831149


Reviewed-by: Sangwhan Moon <sxm@google.com>
Commit-Queue: Sangwhan Moon <sxm@google.com>
Reviewed-by: Cassie Wang <cassiewang@google.com>
Signed-off-by: Richard Fung <richardfung@google.com>