rockchip: rk322x: add pinctrl driver

Add init pinctrl driver support for:
- i2c;
- spi;
- uart;
- pwm;
- emmc/sdmmc;

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>