dt-bindings: clock: qcom: Add SM8550 graphics clock controller

Add device tree bindings for the graphics clock controller on
Qualcomm SM8550 platform.

Signed-off-by: Jagadeesh Kona <quic_jkona@quicinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230524181800.28717-2-quic_jkona@quicinc.com