dt-bindings: dma: qcom,bam: Document dma-coherent property

Qualcomm BAM DMA controller has DMA-coherent support so define it in the
properties section.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Kaushal Kumar <quic_kaushalk@quicinc.com>
Link: https://lore.kernel.org/r/20250423063054.28795-3-quic_kaushalk@quicinc.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>