sunxi: Add defconfig and dts for the Polaroid MID2809PXE4 tablet

The Polaroid MID2809PXE4 is a 9" tablet which is clearly marked
Polaroid MID2809PXE4 on the back. It features a 9" 16:9 800x480 LCD,
A23 Soc, 1GB RAM, 8GB NAND, gsl3670 touchscreen and esp8089 wifi.

The dts file is identical to the one submitted to the upstream kernel.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/board/sunxi/MAINTAINERS b/board/sunxi/MAINTAINERS
index 7c1c025..5535326 100644
--- a/board/sunxi/MAINTAINERS
+++ b/board/sunxi/MAINTAINERS
@@ -55,6 +55,7 @@
 F:	configs/gt90h_v4_defconfig
 F:	configs/orangepi_pc_defconfig
 F:	configs/orangepi_plus_defconfig
+F:	configs/polaroid_mid2809pxe04_defconfig
 F:	configs/q8_a23_tablet_800x480_defconfig
 F:	configs/q8_a33_tablet_800x480_defconfig
 F:	configs/q8_a33_tablet_1024x600_defconfig