davinci: da850-evm: enable driver model for NAND

Enable the driver-model on da850-evm. We need to add a dummy nand node
to the device tree, as the real nand node is a sub-node of the aemif
device.

On linux the aemif driver populates all its child nodes, but we can't do
it in u-boot currently.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Tested-by: Adam Ford <aford173@gmail.com> #da850-evm
diff --git a/arch/arm/dts/da850-evm-u-boot.dtsi b/arch/arm/dts/da850-evm-u-boot.dtsi
index 1683f34..d9e8b99 100644
--- a/arch/arm/dts/da850-evm-u-boot.dtsi
+++ b/arch/arm/dts/da850-evm-u-boot.dtsi
@@ -10,6 +10,10 @@
 	soc@1c00000 {
 		u-boot,dm-spl;
 	};
+
+	nand {
+		compatible = "ti,davinci-nand";
+	};
 };
 
 &flash {