sunxi: add support for Banana Pi M2 Plus board

Banana Pi M2 Plus is an Allwinner H3-based SBC by Sinovoip, which has
already mainline device tree file that have landed into U-Boot source
tree.

Add a defconfig file for it and add the MAINTAINERS items.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
diff --git a/board/sunxi/MAINTAINERS b/board/sunxi/MAINTAINERS
index f39402b..1c88173 100644
--- a/board/sunxi/MAINTAINERS
+++ b/board/sunxi/MAINTAINERS
@@ -280,6 +280,11 @@
 F:	configs/Sinlinx_SinA33_defconfig
 W:	http://linux-sunxi.org/Sinlinx_SinA33
 
+SINOVOIP BPI M2 PLUS H3 BOARD
+M:	Icenowy Zheng <icenowy@aosc.io>
+S:	Maintained
+F:	configs/Sinovoip_BPI_M2_Plus_defconfig
+
 SINOVOIP BPI M3 A83T BOARD
 M:	VishnuPatekar <vishnupatekar0510@gmail.com>
 S:	Maintained