spi: rockchip_sfc: Implement set_speed logic

Set clock related processing into set_speed logic. And Optimize
printing format.

Tested-by: Chris Morgan <macromorgan@hotmail.com>
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
1 file changed