pinctrl: rockchip: Add iomux-route switching support for rk3228

There are 9 IP blocks pin routes need to be switched, that are
pwm-0, pwm-1, pwm-2, pwm-3, sdio, spi, emmc, uart2, uart1.

Signed-off-by: David Wu <david.wu@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>