repohooks: Include mk files in aosp_license check am: aad4d88f1b

Original change: https://android-review.googlesource.com/c/platform/tools/repohooks/+/3296433

Change-Id: I819bbf357d4526a64a6ad1835c62b27f3b3f62c1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>