reset: uniphier: do not use per-SoC macro for system reset block

This macro turned out not so useful as I had expected.

Hardware engineers said they would change reset bit assignments for
every SoC going forward.  This means we can not share the macros
among SoCs.  Just use primitive macros.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>