sh: add support for SH7785

Renesas SH7785 has DDR2-SDRAM controller, PCI, and other.
This patch supports CPU register's header file.

Signed-off-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>