uniphier: make I/O register region configurable

The I/O register region will be changed in the next SoC. Make it
configurable.

Change-Id: Iec0cbd1ef2d0703ebc7c3d3082edd73791bbfec9
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
5 files changed