uniphier: make UART base address configurable

The next SoC supports the same UART, but the register base will be
changed. Make it configurable.

Change-Id: Ida5c9151b2f3554afd15555b22838437eef443f7
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 files changed