ARM: orion5x: Fix typo in device_type property of phy node

This patch fixes a typo for device_type property of phy node.
This can work as of today but once a checks are added in generic code
this typo will stop phy from working.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/boot/dts/orion5x-lacie-ethernet-disk-mini-v2.dts

@@ -58,7 +58,7 @@ &mdio {
 	status = "okay";
 
 	ethphy: ethernet-phy {
-		device-type = "ethernet-phy";
+		device_type = "ethernet-phy";
 		reg = <8>;
 	};
 };