pinctrl: airoha: convert PWM GPIO to macro

The PWM GPIO struct definition follow the same pattern for every GPIO
pin hence it can be converted to a macro.

Create 2 macro one for normal mux and one for ext mux and convert all
the entry to these new macro to reduce code size.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Ansuel