clk: lan966x: make it selectable for ARCH_LAN969X

LAN969x uses the same LAN966x clock driver so make it selectable for
ARCH_LAN969X.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Link: https://lore.kernel.org/r/20241108112355.20251-1-robert.marko@sartura.hr
Signed-off-by: Stephen Boyd <sboyd@kernel.org>