dt-bindings: mfd: bd9571mwv: Document BD9574MWF

Document other similar specification chip BD9574MWF.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/bd9571mwv.txt

-* ROHM BD9571MWV Power Management Integrated Circuit (PMIC) bindings
+* ROHM BD9571MWV/BD9574MWF Power Management Integrated Circuit (PMIC) bindings
 
 Required properties:
- - compatible		: Should be "rohm,bd9571mwv".
+ - compatible		: Should be "rohm,bd9571mwv" or "rohm,bd9574mwf".
  - reg			: I2C slave address.
  - interrupts		: The interrupt line the device is connected to.
  - interrupt-controller	: Marks the device node as an interrupt controller.