The R0P7757LC0030RL board has SH7757, 256MB DDR3-SDRAM, SPI ROM,
Ethernet, and more.

This patch supports the following functions:
 - 256MB DDR3-SDRAM
 - SPI ROM
 - Ethernet

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