dt-bindings: pinctrl: add compatible for Allwinner A523/T527

The A523 contains a pin controller similar to previous SoCs, although
using 10 GPIO banks (PortB-PortK), all of them being IRQ capable.
With this SoC we introduce a new style of binding, where the pinmux values
for each pin group are stored in the new "allwinner,pinmux" property in
the DT node, instead of requiring every driver to store a mapping between
the function names and the required pinmux.

Add a new binding file, since all the different variants of the old
binding are making the file a bit unwieldy to handle already, and the new
property would make the situation worse.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/20250306235827.4895-7-andre.przywara@arm.com


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