dt-bindings: pinctrl: sunxi: Add supply properties

The pinctrl node can have multiple regulators for each of its GPIO banks.
Add the property descriptions.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt

@@ -44,6 +44,19 @@ Note: For backward compatibility reasons, the hosc and losc clocks are only
 required if you need to use the optional input-debounce property. Any new
 device tree should set them.
 
+Each pin bank, depending on the SoC, can have an associated regulator:
+
+- vcc-pa-supply: for the A10, A20, A31, A31s, A80 and R40 SoCs
+- vcc-pb-supply: for the A31, A31s, A80 and V3s SoCs
+- vcc-pc-supply: for the A10, A20, A31, A31s, A64, A80, H5, R40 and V3s SoCs
+- vcc-pd-supply: for the A23, A31, A31s, A64, A80, A83t, H3, H5 and R40 SoCs
+- vcc-pe-supply: for the A10, A20, A31, A31s, A64, A80, R40 and V3s SoCs
+- vcc-pf-supply: for the A10, A20, A31, A31s, A80, R40 and V3s SoCs
+- vcc-pg-supply: for the A10, A20, A31, A31s, A64, A80, H3, H5, R40 and V3s SoCs
+- vcc-ph-supply: for the A31, A31s and A80 SoCs
+- vcc-pl-supply: for the r-pinctrl of the A64, A80 and A83t SoCs
+- vcc-pm-supply: for the r-pinctrl of the A31, A31s and A80 SoCs
+
 Optional properties:
   - input-debounce: Array of debouncing periods in microseconds. One period per
     irq bank found in the controller. 0 if no setup required.