MAINTAINERS: Add maintainer entry of RMOBILE

Add MAINTAINERS entry.
Signed-off-by: NNobuhiro Iwamatsu <iwamatsu@nigauri.org>

MAINTAINERS

@@ -125,6 +125,12 @@ T:	git git://git.denx.de/u-boot-pxa.git
 F:	arch/arm/cpu/pxa/
 F:	arch/arm/include/asm/arch-pxa/
 
+ARM RENESAS RMOBILE/R-CAR
+M:	Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+S:	Maintained
+T:	git git://git.denx.de/u-boot-sh.git
+F:	arch/arm/mach-rmobile/
+
 ARM ROCKCHIP
 M:	Simon Glass <sjg@chromium.org>
 S:	Maintained