clk: rockchip: rk3588: fix CLK_NR_CLKS usage

CLK_NR_CLKS is not part of the DT bindings and needs to be removed
from it, just like it recently happened for other platforms. This
takes care of it by introducing a new function identifying the
maximum used clock ID at runtime.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20240126182919.48402-2-sebastian.reichel@collabora.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>