recipes-bsp/u-boot: Add u-boot_2018.09.bbappend

Use the meta-sunxi u-boot version.
This will apply for boards which  do
not set a PREFERRED_VERSION for u-boot.

Signed-off-by: Vicentiu Galanopulo <vicentiu@balena.io>

layers/meta-balena-allwinner/recipes-bsp/u-boot/files/0001-nanopi_neo_air_defconfig-Enable-eMMC-support.patch

@@ -0,0 +1,26 @@
+From f4a77da23b3890b53efab6a927cbe99b76ef3b26 Mon Sep 17 00:00:00 2001
+From: Florin Sarbu <florin@resin.io>
+Date: Wed, 12 Sep 2018 14:22:49 +0200
+Subject: [PATCH] nanopi_neo_air_defconfig: Enable eMMC support
+
+Upstream-status: Pending
+Signed-off-by: Florin Sarbu <florin@resin.io>
+---
+ configs/nanopi_neo_air_defconfig | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/configs/nanopi_neo_air_defconfig b/configs/nanopi_neo_air_defconfig
+index ca9c2dd..74ce044 100644
+--- a/configs/nanopi_neo_air_defconfig
++++ b/configs/nanopi_neo_air_defconfig
+@@ -10,6 +10,7 @@ CONFIG_DEFAULT_DEVICE_TREE="sun8i-h3-nanopi-neo-air"
+ # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+ CONFIG_CONSOLE_MUX=y
+ CONFIG_SPL=y
++CONFIG_MMC_SUNXI_SLOT_EXTRA=2
+ # CONFIG_CMD_FLASH is not set
+ # CONFIG_SPL_DOS_PARTITION is not set
+ # CONFIG_SPL_ISO_PARTITION is not set
+-- 
+2.7.4
+