dt-bindings: pinctrl: rockchip: increase max amount of device functions

RK3588 can have 10 different device functions, so increase the maximum
amount appropriately. Considering rockchip uses auto-generated pinmux
files, adding a quite complex if construct to increase the limit just
for rk3588 does not seem to be worth the effort.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220504213251.264819-19-sebastian.reichel@collabora.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/rockchip,pinctrl.yaml

@@ -131,7 +131,7 @@ additionalProperties:
               description:
                 Pin bank index.
             - minimum: 0
-              maximum: 6
+              maximum: 10
               description:
                 Mux 0 means GPIO and mux 1 to N means
                 the specific device function.