sh: add support for sh7757lcr board

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>
diff --git a/boards.cfg b/boards.cfg
index 141b143..a97d30c 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -745,6 +745,7 @@
 ap325rxa                     sh          sh4         ap325rxa            renesas        -
 r2dplus                      sh          sh4         r2dplus             renesas        -
 r7780mp                      sh          sh4         r7780mp             renesas        -
+sh7757lcr                    sh          sh4         sh7757lcr           renesas        -
 sh7763rdp                    sh          sh4         sh7763rdp           renesas        -
 sh7785lcr                    sh          sh4         sh7785lcr           renesas        -
 sh7785lcr_32bit              sh          sh4         sh7785lcr           renesas        -           sh7785lcr:SH_32BIT=1