Android.mk: import LICENSE indicators from AOSP

https://android-review.googlesource.com/c/platform/external/libvpx/+/1588942
https://android.googlesource.com/platform/external/libvpx/+/099828b5c770ef8630741721be4b6c25a8394204

Change-Id: Ieca1c882f82bcbc7546944b43af7fab358f925d2
1 file changed