dt-bindings: PCI: Fix legacy-interrupt-controller #interrupt-cells to be '2'

Modify #interrupt-cells of legacy-interrupt-controller to be '2' in
order to set the correct interrupt type.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

Documentation/devicetree/bindings/pci/pci-keystone.txt

@@ -46,12 +46,12 @@ ti,syscon-pcie-mode : phandle to the device control module required to configure
 	};
 
 pcie_intc: Interrupt controller device node for Legacy IRQ chip
-	interrupt-cells: should be set to 1
+	interrupt-cells: should be set to 2
 
  Example:
 	pcie_intc: legacy-interrupt-controller {
 		interrupt-controller;
-		#interrupt-cells = <1>;
+		#interrupt-cells = <2>;
 		interrupt-parent = <&gic>;
 		interrupts = <GIC_SPI 26 IRQ_TYPE_EDGE_RISING>,
 			<GIC_SPI 27 IRQ_TYPE_EDGE_RISING>,