dt-bindings: gpio: add QIXIS FPGA based GPIO controller

Add a device tree binding for the QIXIS FPGA based GPIO controller.
Depending on the board, the QIXIS FPGA exposes registers which act as a
GPIO controller, each with 8 GPIO lines of fixed direction.

Since each QIXIS FPGA layout has its particularities, add a separate
compatible string for each board/GPIO register combination supported.

Since these GPIO controllers are trivial, make use of the newly added
trivial-gpio.yaml file instead of creating an entirely new one.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Documentation/devicetree/bindings/gpio/trivial-gpio.yaml

@@ -22,6 +22,8 @@ properties:
           - cznic,moxtet-gpio
           - dlg,slg7xl45106
           - fcs,fxl6408
+          - fsl,ls1046aqds-fpga-gpio-stat-pres2
+          - fsl,lx2160ardb-fpga-gpio-sfp
           - gateworks,pld-gpio
           - ibm,ppc4xx-gpio
           - loongson,ls1x-gpio