Removed unused Android.mk under device/google/contexthub am: 224d08b385 am: c182afa2f3

Original change: https://android-review.googlesource.com/c/device/google/contexthub/+/3099157

Change-Id: I33a27b1bbf0ddc3c8878a202ecfe592505a48515
Signed-off-by: Automerger Merge Worker <[email protected]>