Remove unused Android.mk under device/google/redfin am: a9544cd2ed am: 65df820ad4

Original change: https://android-review.googlesource.com/c/device/google/redfin/+/2836011

Change-Id: Ied8d486a0f2ab48acad2971f50a03f01801465fc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>