dt-bindings: clock: add clock definitions and documentation for exynos7870 CMU

dt-bindings: clock: add clock definitions and documentation for exynos7870 CMU

Add unique identifiers for exynos7870 clocks for every bank. It adds all
clocks of CMU_MIF, CMU_DISPAUD, CMU_G3D, CMU_ISP, CMU_MFCMSCL, and
CMU_PERI. Document the devicetree bindings as well.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250301-exynos7870-pmu-clocks-v5-1-715b646d5206@disroot.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>