Set min_sdk_version am: 50859d4d50

Original change: https://android-review.googlesource.com/c/platform/external/gemmlowp/+/2138435

Change-Id: Ide040bf73aa661c2478ea8e12ed8aa717ce9f2f1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>