ARM: hisi: rename secondary_startup function

As hix5hd2 and hip01 has the same secondary_startup
so rename hix5hd2_secondary_startup to
to hisi_secondary_startup.

the hip01 will use hisi_secondary_startup for the
secondary core boot.

Signed-off-by: Wang Long <long.wanglong@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>
Signed-off-by: Olof Johansson <olof@lixom.net>