clk: rockchip: rk3399: Support module build

clk: rockchip: rk3399: Support module build

support CLK_OF_DECLARE and builtin_platform_driver_probe
double clk init method.
add module author, description and license to support building
Soc Rk3399 clock driver as module.

Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20200914022316.24045-1-zhangqing@rock-chips.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>