Fix to boot.img (I hope)

Here: https://github.com/davidkorku/device_xiaomi_cancro/commit/7efa6daf641ef36a079804a5a546e657138def21 you delete "PRODUCT_COPY_FILES" to change for "PRODUCT_PACKAGES" but you forgot "include $(BUILD_PREBUILT)" in some packages, for example init.qcom.rc and those files aren´t copied to the boot image