uboot-imx

sh: Add Renesas rsk7264 board

The rsk7264 (also know as rsk2+sh7264) is an SH2A based board
with 64MB NAND flash and 64MB SDRAM. It is very similar to the
rsk7203 board.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>