dt-bindings: mfd: max77620: Add compatible for Maxim 77663

Maxim 77663 has a few minor differences in regards to hardware interface
and available capabilities by comparing it with 77620 and 20024 models,
hence re-use 77620 device-tree binding for the 77663.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Documentation/devicetree/bindings/mfd/max77620.txt

@@ -4,7 +4,8 @@ Required properties:
 -------------------
 - compatible: Must be one of
 		"maxim,max77620"
-		"maxim,max20024".
+		"maxim,max20024"
+		"maxim,max77663"
 - reg: I2C device address.
 
 Optional properties:
@@ -105,6 +106,7 @@ Optional properties:
 Here supported time periods by device in microseconds are as follows:
 MAX77620 supports 40, 80, 160, 320, 640, 1280, 2560 and 5120 microseconds.
 MAX20024 supports 20, 40, 80, 160, 320, 640, 1280 and 2540 microseconds.
+MAX77663 supports 20, 40, 80, 160, 320, 640, 1280 and 2540 microseconds.
 
 -maxim,power-ok-control: configure map power ok bit
 			1: Enables POK(Power OK) to control nRST_IO and GPIO1