dt-bindings: gpio-vf610: add imx7ulp support

The Rapid General-Purpose Input and Output with 2 Ports (RGPIO2P)
on MX7ULP is similar to GPIO on Vibrid, except it has an extra
Port Data Direction Register (PDDR) used to configure the individual
port pins for input or output.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Stefan Agner <stefan@agner.ch>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/gpio-vf610.txt

@@ -5,7 +5,9 @@ functionality. Each pair serves 32 GPIOs. The VF610 has 5 instances of
 each, and each PORT module has its own interrupt.
 
 Required properties for GPIO node:
-- compatible : Should be "fsl,<soc>-gpio", currently "fsl,vf610-gpio"
+- compatible : Should be "fsl,<soc>-gpio", below is supported list:
+	       "fsl,vf610-gpio"
+	       "fsl,imx7ulp-gpio"
 - reg : The first reg tuple represents the PORT module, the second tuple
   the GPIO module.
 - interrupts : Should be the port interrupt shared by all 32 pins.