dt-bindings: pinctrl: update pcie/pwm/spi bindings for MT7986 SoC

Allow multiple items for pcie, pwm and spi function.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221106080114.7426-2-linux@fw-web.de


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