dt-bindings: gpio: fsl-imx-gpio: add i.MX ARMv6 and ARMv7 compatibles

Several DTSes with ARMv6 and ARMv7 i.MX SoCs introduce their own
compatibles so add them to fix dtbs_check warnings like:

  arch/arm/boot/dts/imx35-pdk.dt.yaml: gpio@53fa4000:
    compatible: ['fsl,imx35-gpio', 'fsl,imx31-gpio'] is not valid under any of the given schemas

  arch/arm/boot/dts/imx51-babbage.dt.yaml: gpio@73f90000:
    compatible: ['fsl,imx51-gpio', 'fsl,imx35-gpio'] is not valid under any of the given schemas
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200920195848.27075-2-krzk@kernel.orgSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/gpio/fsl-imx-gpio.yaml

@@ -18,8 +18,20 @@ properties:
           - fsl,imx31-gpio
           - fsl,imx35-gpio
           - fsl,imx7d-gpio
+      - items:
+          - const: fsl,imx35-gpio
+          - const: fsl,imx31-gpio
       - items:
           - enum:
+              - fsl,imx50-gpio
+              - fsl,imx51-gpio
+              - fsl,imx53-gpio
+              - fsl,imx6q-gpio
+              - fsl,imx6sl-gpio
+              - fsl,imx6sll-gpio
+              - fsl,imx6sx-gpio
+              - fsl,imx6ul-gpio
+              - fsl,imx7d-gpio
               - fsl,imx8mm-gpio
               - fsl,imx8mn-gpio
               - fsl,imx8mp-gpio