wandboard: Sync with devicetree files from kernel 5.1.9

Udate the wandboard devicetree files with the ones
from kernel 5.1.9.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
diff --git a/arch/arm/dts/imx6dl-wandboard-revb1.dts b/arch/arm/dts/imx6dl-wandboard-revb1.dts
index 738db4f..c2946fb 100644
--- a/arch/arm/dts/imx6dl-wandboard-revb1.dts
+++ b/arch/arm/dts/imx6dl-wandboard-revb1.dts
@@ -13,6 +13,7 @@
 	compatible = "wand,imx6dl-wandboard", "fsl,imx6dl";
 
 	memory@10000000 {
+		device_type = "memory";
 		reg = <0x10000000 0x40000000>;
 	};
 };