dt-bindings: usb: dwc3: Add interrupt-names property support

The controller driver supports two types of DWC USB3 devices: with a
common interrupt lane and with individual interrupts for each mode. Add
support for both these cases to the DWC USB3 DT schema.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201210090944.16283-12-Sergey.Semin@baikalelectronics.ruSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/snps,dwc3.yaml

@@ -34,8 +34,19 @@ properties:
       const: snps,dwc3
 
   interrupts:
+    description:
+      It's either a single common DWC3 interrupt (dwc_usb3) or individual
+      interrupts for the host, gadget and DRD modes.
+    minItems: 1
+    maxItems: 3
+
+  interrupt-names:
     minItems: 1
     maxItems: 3
+    oneOf:
+      - const: dwc_usb3
+      - items:
+          enum: [host, peripheral, otg]
 
   clocks:
     description: