sh: Add support for r0p7734 board

The r0p7734 board has SH7734, 128MB DDR2-SDRAM, USB,
Ethernet, and more.

This patch supports the following functions:
- 128MB DDR2-SDRAM
- 32MB NOR Flash memory
- Serial console (SCIF)
- Ethernet (SH-Ether/SMSC)

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/boards.cfg b/boards.cfg
index 0dee43f..50adef3 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -1028,6 +1028,7 @@
 sh7763rdp                    sh          sh4         sh7763rdp           renesas        -
 sh7785lcr                    sh          sh4         sh7785lcr           renesas        -
 sh7785lcr_32bit              sh          sh4         sh7785lcr           renesas        -           sh7785lcr:SH_32BIT=1
+r0p7734                      sh          sh4         r0p7734             renesas        -
 grsim_leon2                  sparc       leon2       -                   gaisler
 gr_cpci_ax2000               sparc       leon3       -                   gaisler
 gr_ep2s60                    sparc       leon3       -                   gaisler