[U-Boot] rockchip: pinctrl: rk3368: add pinctrl for SDMMC0

[Philipp Tomsich]

> Apparently, our earlier assumption that the BROM will always set up
> the iomux for SDcard communication does not always hold true: when
> booting U-Boot from the on-module (on the RK3368-uQ7) eMMC, the SDcard
> pins are not set up and need to be configured by the pinctrl driver to
> allow SD card access.
> 
> This change implements support for setting up the SDMMC pins in
> pinctrl for the RK3368.
> 
> Reported-by: Klaus Goger <klaus.goger at theobroma-systems.com>
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
> 
>  drivers/pinctrl/rockchip/pinctrl_rk3368.c | 39 +++++++++++++++++++++++++++----
>  1 file changed, 34 insertions(+), 5 deletions(-)
> 

Applied to u-boot-rockchip, thanks!