Update compatible string for hikey960. HiKey960 is a develpment board built
with SoC Hi3660.
Signed-off-by: NGuodong Xu <guodong.xu@linaro.org>
Signed-off-by: NChen Feng <puck.chen@hisilicon.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NWei Xu <xuwei5@hisilicon.com>