[LSC] Add LOCAL_LICENSE_KINDS to external/exoplayer

Added SPDX-license-identifier-Apache-2.0 to:
  Android.bp
  tree/extensions/ffmpeg/src/main/jni/Android.mk
  tree/extensions/flac/src/main/jni/Android.mk
  tree/extensions/opus/src/main/jni/Android.mk
  tree/extensions/opus/src/main/jni/libopus.mk
  tree/extensions/vp9/src/main/jni/Android.mk
  tree/extensions/vp9/src/main/jni/libvpx.mk

Bug: 68860345
Bug: 151177513
Bug: 151953481

Test: m all

Exempt-From-Owner-Approval: janitorial work
Change-Id: Id966ec3b31c8d725244ad8babc1d2f7b7abb0cd5
7 files changed