After discussion with the devicetree maintainers we agreed to not extend
lists with the generic compatible "apple,pinctrl" anymore [1]. Use
"apple,t8103-pinctrl" as fallback compatible as it is the SoC driver and
bindings were originally written for.
The t602x (M2 Pro/Max/Ultra) devicetrees submitted in [2] use this
compatible as fallback instead of "apple,t8103-pinctrl".