clk: canaan: Add clock driver for Canaan K230

clk: canaan: Add clock driver for Canaan K230

This patch provides basic support for the K230 clock, which covers
all clocks in K230 SoC.

The clock tree of the K230 SoC consists of a 24MHZ external crystal
oscillator, PLLs and an external pulse input for timerX, and their
derived clocks.

Co-developed-by: Troy Mitchell <TroyMitchell988@gmail.com>
Signed-off-by: Troy Mitchell <TroyMitchell988@gmail.com>
Signed-off-by: Xukai Wang <kingxukai@zohomail.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>