board: Add Bananapi M1 support

Add initial support for bananapi M1 board with below features:
- U-Boot 2017.09
- Linux 4.13.7
- Default packages from buildroot

Cc: Jason <manager@sinovoip.com.cn>
Cc: hailymei@banana-pi.com <hailymei@banana-pi.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
diff --git a/DEVELOPERS b/DEVELOPERS
index ac1bc9c..448dd4b 100644
--- a/DEVELOPERS
+++ b/DEVELOPERS
@@ -727,7 +727,9 @@
 F:	package/keepalived/
 
 N:	Jagan Teki <jagan@amarulasolutions.com>
+F:	board/bananapi/
 F:	board/engicam/
+F:	configs/bananapi_m1_defconfig
 F:	configs/engicam_imx6qdl_icore_defconfig
 F:	configs/engicam_imx6qdl_icore_qt5_defconfig
 F:	configs/engicam_imx6qdl_icore_rqs_defconfig