pinctrl: axp209: add missing Kconfig dependencies

This fixes some compilation issues.

GENERIC_PINCONF and OF at least for pinconf_generic_dt_*, PINMUX at
least for pinmux_ops and GPIOLIB for at least gpio_chip.

Fixes: 23f75d7d ("pinctrl: axp209: add pinctrl features")

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>