[U-Boot] [U-Boot, v2] rockchip: rk3188: use board_debug_uart_init() for UART io init

[Philipp Tomsich]

> Sync with other rockchip SoCs, use board_debug_uart_init() to
> init default UART iomux.
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
> Changes in v2:
> - rebase on uboot-rockchip/master
> 
>  arch/arm/mach-rockchip/Kconfig            |  1 +
>  arch/arm/mach-rockchip/rk3188-board-spl.c | 28 ++++++++++++++---------
>  2 files changed, 18 insertions(+), 11 deletions(-)
> 

Applied to u-boot-rockchip, thanks!