iio: hx711: fix spurious unit-address in example

Device tree compiler (dtc) gives a warning if a device node has "@" with a
following number as it's name but no reg property.

Fix the example in the documentation of avia,hx711 to conform to dtc
behavior.
Signed-off-by: NAndreas Klinger <ak@it-klinger.de>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/avia-hx711.txt

@@ -14,7 +14,7 @@ Optional properties:
 			high time of 50 microseconds.
 
 Example:
-weight@0 {
+weight {
 	compatible = "avia,hx711";
 	sck-gpios = <&gpio3 10 GPIO_ACTIVE_HIGH>;
 	dout-gpios = <&gpio0 7 GPIO_ACTIVE_HIGH>;