configs: add PineTab defconfig

The PineTab device-tree is already in u-boot, this commit adds the
corresponding defconfig, based on pinephone_defconfig.

Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/board/sunxi/MAINTAINERS b/board/sunxi/MAINTAINERS
index 4fc2607..2543c94 100644
--- a/board/sunxi/MAINTAINERS
+++ b/board/sunxi/MAINTAINERS
@@ -471,6 +471,11 @@
 S:	Maintained
 F:	configs/pinephone_defconfig
 
+PINETAB BOARD
+M:	Arnaud Ferraris <arnaud.ferraris@collabora.com>
+S:	Maintained
+F:	configs/pinetab_defconfig
+
 R16 EVB PARROT BOARD
 M:	Quentin Schulz <quentin.schulz@free-electrons.com>
 S:	Maintained