dt-bindings: clock: rk3576: add IOC gated clocks

Certain clocks on the RK3576 are additionally essentially "gated" behind
some bit toggles in the IOC GRF range. Downstream ungates these by
adding a separate clock driver that maps over the GRF range and leaks
their implementation of this into the DT.

Instead, define some new clock IDs for these, so that consumers of these
types of clocks can properly articulate which clock they're using, so
that we can then add them to the clock driver for SoCs that need them.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20250502-rk3576-sai-v3-1-376cef19dd7c@collabora.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>