dt-bindings: pinctrl: qcom,sm8250-pinctrl: do not require function on non-GPIOs

Certain pins, like SDcard related, do not have functions and such should
not be required:

  sdc1-clk-pins: 'function' is a required property

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220912061746.6311-14-krzysztof.kozlowski@linaro.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/qcom,sm8250-pinctrl.yaml

@@ -110,7 +110,15 @@ patternProperties:
 
       required:
         - pins
-        - function
+
+      allOf:
+        - if:
+            properties:
+              pins:
+                pattern: "^gpio([0-9]|[1-9][0-9]|1[0-7][0-9])$"
+          then:
+            required:
+              - function
 
       additionalProperties: false