davinci: omapl138-lcdk: enable driver model for NAND

Enable the driver-model on da850-lcdk. 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>

arch/arm/dts/da850-lcdk-u-boot.dtsi

@@ -9,4 +9,8 @@
 	aliases {
 		i2c0 = &i2c0;
 	};
+
+	nand {
+		compatible = "ti,davinci-nand";
+	};
 };