ANDROID: cuttlefish: overlayfs: regression

commit a77712c3
("ANDROID: Remove unused cuttlefish build infra") caused a
regression in availability of CONFIG_OVERLAY_FS configuration.

NB: The upstream work to add override_creds to overlayfs is
    required in order to pass adb-remount-test.sh.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Test: confirm overlay filesystem available in the build
Bug: 138649540
Change-Id: I9e51475f1025f726e69c6f513099248bf452cc2d