Documentation: DT: qcom_hidma: update binding for MSI

Adding a new binding for qcom,hidma-1.1 to distinguish HW supporting
MSI interrupts from the older revision.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

Documentation/devicetree/bindings/dma/qcom_hidma_mgmt.txt

@@ -47,12 +47,18 @@ When the OS is not in control of the management interface (i.e. it's a guest),
 the channel nodes appear on their own, not under a management node.
 
 Required properties:
-- compatible: must contain "qcom,hidma-1.0"
+- compatible: must contain "qcom,hidma-1.0" for initial HW or "qcom,hidma-1.1"
+for MSI capable HW.
 - reg: Addresses for the transfer and event channel
 - interrupts: Should contain the event interrupt
 - desc-count: Number of asynchronous requests this channel can handle
 - iommus: required a iommu node
 
+Optional properties for MSI:
+- msi-parent : See the generic MSI binding described in
+ devicetree/bindings/interrupt-controller/msi.txt for a description of the
+ msi-parent property.
+
 Example:
 
 Hypervisor OS configuration: