dt-bindings: pinctrl: mediatek: mt7986: fix patternProperties regex

Set second level patternProperties to '^.*mux.*$' and '^.*conf.*$' on
mediatek,mt7986-pinctrl.yaml to be on par with other schemas.

Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230317213011.13656-19-arinc.unal@arinc9.com


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