dt-bindings: clock: google,gs101-clock: Add DPU clock management unit

dt-bindings: clock: google,gs101-clock: Add DPU clock management unit

Add dt schema documentation and clock IDs for the Display Process Unit
(DPU) clock management unit (CMU). This CMU feeds IPs such as image scaler,
enhancer and compressor.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: André Draszik <andre.draszik@linaro.org>
Link: https://patch.msgid.link/20260113-dpu-clocks-v3-2-cb85424f2c72@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>