clk: rockchip: Use clk_hw_register_composite instead of clk_register_composite calls

clk_hw_register_composite it's already exported.
Preparation for compilation of rK common clock drivers into modules.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20200914022225.23613-2-zhangqing@rock-chips.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>