dt-bindings: usb: fix example hub node name

According to the OF Recommended Practice for USB, hub nodes shall be
named "hub", but the example had mixed up the label and node names. Fix
the node name and drop the redundant label.

While at it, remove a newline and add a missing semicolon to the example
source.

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/usb/usb-device.txt

@@ -16,12 +16,11 @@ Required properties:
 Example:
 
 &usb1 {
-
 	#address-cells = <1>;
 	#size-cells = <0>;
 
-	hub: genesys@1 {
+	hub@1 {
 		compatible = "usb5e3,608";
 		reg = <1>;
 	};
-}
+};