aarch64: Add Huawei Kunpeng to tunable cpu list

Kunpeng processer is a 64-bit Arm-compatible CPU released by Huawei,
and we have already signed a copyright assignement with the FSF.

This patch adds its to cpu list, and related macro for IFUNC.

Checked on aarch64-linux-gnu.

Reviewed-by: Szabolcs Nagy <Szabolcs.Nagy@arm.com>