dt-bindings: qcom-bam: Add 'interconnects' & 'interconnect-names' to optional properties

Add new optional properties - 'interconnects' and
'interconnect-names' to the device-tree binding documentation for
qcom-bam DMA IP.

These properties describe the interconnect path between bam and main
memory and the interconnect type respectively.

Cc: Thara Gopinath <thara.gopinath@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>