db845c|rb5: Switch to android-6.6 as the default kernel version am: e969c450d2 am: 2eb981d5d1

Original change: https://android-review.googlesource.com/c/device/linaro/dragonboard/+/3018836

Change-Id: Ic312ddaf6753064ca15d30e60a2f1525ecbdc29e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>