[U-Boot] [U-Boot, 15/36] rockchip: declare sdram_init() in common header

[Philipp Tomsich]

> We need a dedicate sdram_init() function for those SoCS not
> using SPL_FRAMEWORK.
> 
> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
> ---
> 
>  arch/arm/include/asm/arch-rockchip/sys_proto.h | 3 +++
>  1 file changed, 3 insertions(+)
> 

Acked-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>