clk: rockchip: Add support for multiple clock providers

There are need to support Multi-CRUs probability in future, but
it is not supported on the current Rockchip Clock Framework.

Therefore, this patch add support a provider as the parameter
handler when we call the clock register functions for per CRU.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>