ARM: debug: add HiP01 debug uart

Add the support of Hisilicon HiP01 debug uart.
The uart of hip01 is 8250 compatible.

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>