dt-bindings: pinctrl: uniphier: Add child node definitions to describe pin mux and configuration

In arch/arm/boot/dts/uniphier-pinctrl.dtsi, there are child nodes of
pinctrl that defines pinmux and pincfg, however, there are no rules about
that in dt-bindings.

'make dtbs_check' results an error with the following message:

   pinctrl: 'ain1', 'ain2', 'ainiec1', 'aout', 'aout1', 'aout2', ...
   ... 'usb2', 'usb3' do not match any of the regexes: 'pinctrl-[0-9]+'

To avoid the issue, add the rules of pinmux and pincfg in each child node
and grandchild node.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1636416699-21033-1-git-send-email-hayashi.kunihiko@socionext.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>