rockchip: rk3399: Add Nanopi M4 2GB board support

commit b2f5da9dd068 ("rockchip: rk3399: Add Nanopi M4 board support") added
support for Nanopi M4 board with Dual-Channel 4GB LPDDR3-1866 RAM.
This patch adds another variant of NanoPi M4 board with Dual-Channel
2GB DDR3-1866 RAM.

Signed-off-by: Deepak Das <deepakdas.linux@gmail.com>
diff --git a/board/rockchip/evb_rk3399/MAINTAINERS b/board/rockchip/evb_rk3399/MAINTAINERS
index 0834254..792df10 100644
--- a/board/rockchip/evb_rk3399/MAINTAINERS
+++ b/board/rockchip/evb_rk3399/MAINTAINERS
@@ -42,6 +42,13 @@
 F:	configs/nanopi-m4-rk3399_defconfig
 F:	arch/arm/dts/rk3399-nanopi-m4-u-boot.dtsi
 
+NANOPI-M4-2GB
+M:	Jagan Teki <jagan@amarulasolutions.com>
+M:	Deepak Das <deepakdas.linux@gmail.com>
+S:	Maintained
+F:	configs/nanopi-m4-2gb-rk3399_defconfig
+F:	arch/arm/dts/rk3399-nanopi-m4-2gb-u-boot.dtsi
+
 NANOPI-NEO4
 M:	Jagan Teki <jagan@amarulasolutions.com>
 S:	Maintained