arm64: apple: Add pinctrl nodes

Add pinctrl nodes corresponding to the gpio,t8101 nodes in the
Apple device tree for the Mac mini (M1, 2020).

Clock references are left out at the moment and will be added once
the appropriate bindings have been settled upon.

Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210520171310.772-3-mark.kettenis@xs4all.nl
Signed-off-by: Hector Martin <marcan@marcan.st>