overlay: overlay the overlay with moar overlays

    On dlxj, we need to overlay our own kddi eri.xml's because these break
    other devices (namely toro) by causing a roaming icon. Ours does the
    opposite if we don't have them.

    Also need to switch to using PRODUCT_PACKAGE_OVERLAYS instead of
    DEVICE_PACKAGE_OVERLAYS and inherit it before vendor/cm/ overlays or it won't
    take effect.

Change-Id: I2dd5bbf992796e4a3871de72e5632c8c04ccfa3f