dt-bindings: pinctrl: airoha: Document AN7583 Pin Controller

Document Airoha AN7583 Pin Controller based on Airoha EN7581 with some
minor difference on some function group (PCM and LED gpio).

To not bloat the EN7581 schema with massive if condition, use a
dedicated YAML schema for Airoha AN7583.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Ansuel