dt-bindings: interrupt-controller: msi: Add msi-ranges property

Update the MSI controller binding to add an msi-ranges property
that specifies how MSIs map onto regular interrupts on some other
interrupt controller.

Acked-by: Marc Zyngier <[e-mail]>
Signed-off-by: Mark Kettenis <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/interrupt-controller/msi-controller.yaml

···
       Identifies the node as an MSI controller.
     $ref: /schemas/types.yaml#/definitions/flag
 
+  msi-ranges:
+    description:
+      A list of <phandle intspec span> tuples, where "phandle" is the
+      parent interrupt controller, "intspec" is the starting/base
+      interrupt specifier and "span" is the size of the
+      range. Multiple ranges can be provided.
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+
 dependencies:
   "#msi-cells": [ msi-controller ]