Revert "dt-bindings: iio: vadc: Fix documentation of 'reg'"

This reverts commit 7028cae1.

Already picked up via iio tree.
Signed-off-by: Andy Gross <andy.gross@linaro.org>

Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt

@@ -13,7 +13,7 @@ VADC node:
 - reg:
     Usage: required
     Value type: <prop-encoded-array>
-    Definition: VADC base address in the SPMI PMIC register map.
+    Definition: VADC base address and length in the SPMI PMIC register map.
 
 - #address-cells:
     Usage: required
@@ -104,7 +104,7 @@ Example:
 	/* VADC node */
 	pmic_vadc: vadc@3100 {
 		compatible = "qcom,spmi-vadc";
-		reg = <0x3100>;
+		reg = <0x3100 0x100>;
 		interrupts = <0x0 0x31 0x0 IRQ_TYPE_EDGE_RISING>;
 		#address-cells = <1>;
 		#size-cells = <0>;