hikey960: set default kernel to 5.10 am: 7788ffd9eb am: a356ea0c83

Original change: https://android-review.googlesource.com/c/device/linaro/hikey/+/2469591

Change-Id: I05a0342ed18251094b6f026f5d1bf780a0aca111
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>