Merge "hikey.mk/hikey960.mk: add support for android-mainline kernel" am: d90872832e am: d1d0203a85

Original change: https://android-review.googlesource.com/c/device/linaro/hikey/+/1509788

Change-Id: Ib80e15efa3dc9fd93154a10ba89f6184e0cd18b4