regulator: act8865: add act8846 to DT binding documentation

This patch adds a new "active-semi,act8846" compatible string and a
list of supported regulator names to the devicetree binding
documentation for Active-Semi PMUs.
Signed-off-by: NBeniamino Galvani <b.galvani@gmail.com>
Reviewed-by: NAxel Lin <axel.lin@ingics.com>
Signed-off-by: NMark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/regulator/act8865-regulator.txt

-ACT8865 regulator
+ACT88xx regulators
 -------------------
 
 Required properties:
-- compatible: "active-semi,act8865"
+- compatible: "active-semi,act8846" or "active-semi,act8865"
 - reg: I2C slave address
 
 Any standard regulator properties can be used to configure the single regulator.
 
 The valid names for regulators are:
+	- for act8846:
+	REG1, REG2, REG3, REG4, REG5, REG6, REG7, REG8, REG9, REG10, REG11, REG12
+	- for act8865:
 	DCDC_REG1, DCDC_REG2, DCDC_REG3, LDO_REG1, LDO_REG2, LDO_REG3, LDO_REG4.
 
 Example: