Fix vndk packaging to stop depending on phony targets

These had been depending on the phony target for the library
(liblz4.vendor), not the actual built file and notice file.

Since we hadn't been saving the NOTICE file, and were only assuming the
installed notice file path. save that away for use during packaging.

Test: m vndk; diff out/target/product/generic/android-vndk-aosp_arm.zip
Test: m vndk; diff out/target/product/generic_arm64/android-vndk-aosp_arm64.zip
Change-Id: If9a4bed27030b7bd464cd3987739df94d32a0037