clk: lan966x: prepare driver for lan969x support

In preparation for lan969x support, add private match data for lan966x
and add variables for: peripheral clock names, clock gate names, number
of total clocks and number of generic clocks. Use the variables
throughout.

Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://lore.kernel.org/r/20240916-lan969x-clock-v1-3-0e150336074d@microchip.com


[claudiu.beznea: in lan966x_clk_probe(): keep struct_size() arguments on
 a single line]
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>