arm64: dts: uniphier: change cpu-release-address

At first, 256 byte of the head of DRAM space was reserved for some
reasons.  However, as the progress of development, it turned out
unnecessary, and it was never used in the end.  Move the CPU release
address to leave no space.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>