[U-Boot] rockchip: pinctrl: rk3399: add support for I2C8

[Philipp Tomsich]

> The RK3399 has a total of 9 I2C controllers.  To support these, the
> enum in periph.h is extended and the mapping from the IRQ numbers to
> the peripheral-ids is extended to ensure that pinctrl requests are
> passed through to the function configuring the I2C pins.
> 
> For I2C8, the pinctrl is implemented and tested (on a RK3399-Q7) using
> communication with the FAN53555 connected on I2C8.
> 
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Tested-by: Klaus Goger <klaus.goger at theobroma-systems.com>
> ---
> 
>  arch/arm/include/asm/arch-rockchip/grf_rk3399.h |  7 ++++++-
>  arch/arm/include/asm/arch-rockchip/periph.h     |  3 +++
>  drivers/pinctrl/rockchip/pinctrl_rk3399.c       | 19 +++++++++++++++++++
>  3 files changed, 28 insertions(+), 1 deletion(-)
> 

Applied to u-boot-rockchip, thanks!