clk: lan966x: add support for lan969x SoC clock driver

clk: lan966x: add support for lan969x SoC clock driver

Add support for the lan969x SoC clock driver in the existing lan966x
driver. The lan969x clock controller contains 3 PLLs - cpu_clk, ddr_clk
and sys_clk (same as lan966x) which generates and supplies the clock to
various peripherals within the SoC.

Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/20240916-lan969x-clock-v1-4-0e150336074d@microchip.com
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>