ARM: dts: vf610-zii-dev-rev-b: specify phy-mode for external PHYs

Specify the phy-mode for the external PHYs on the third switch on the
ZII development rev B board so phylink and phylib knows what mode these
interfaces are configured for.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/vf610-zii-dev-rev-b.dts

@@ -211,12 +211,14 @@
 						reg = <0>;
 						label = "lan6";
 						phy-handle = <&switch2phy0>;
+						phy-mode = "sgmii";
 					};
 
 					port@1 {
 						reg = <1>;
 						label = "lan7";
 						phy-handle = <&switch2phy1>;
+						phy-mode = "sgmii";
 					};
 
 					port@2 {