[U-Boot] rockchip: timer: make register sizes explicit

[Philipp Tomsich]

> We are about to reuse the rockchip timer (header file) for 64bit ARMv8
> chips, so it seems a good time to make the register sizes explicit by
> changing from 'unsigned int' to 'u32'.
> 
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> ---
> 
>  arch/arm/include/asm/arch-rockchip/timer.h | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 

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