dt-bindings: pinctrl: apple,pinctrl: Add apple,t6020-pinctrl compatible

dt-bindings: pinctrl: apple,pinctrl: Add apple,t6020-pinctrl compatible

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 the driver
and bindings were written for.

The M2 Pro/Max/Ultra SoCs use the same pinctrl hardware, so just add its
per-SoC compatible using the new base as fallback.

[1]: https://lore.kernel.org/asahi/12ab93b7-1fc2-4ce0-926e-c8141cfe81bf@kernel.org/

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Janne Grunau <j@jannau.net>