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/MAINTAINERS b/MAINTAINERS
index 14d06ca..f20448a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1025,6 +1025,7 @@
 Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
 
 	MS7720SE	SH7720
+	R0P77570030RL	SH7757
 	R0P77850011RL	SH7785
 
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