dt-bindings: clock: add QCOM SM6115 display clock bindings

Add device tree bindings for display clock controller for
Qualcomm Technology Inc's SM6115 SoC.

Signed-off-by: Adam Skladowski <a39.skl@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
[bjorn: Minor fix of binding description]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220911164635.182973-2-a39.skl@gmail.com