ARM: dts: r8a7743: Add default PCIe bus clock

This patch adds a default PCIe bus clock node.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7743.dtsi

@@ -1189,6 +1189,13 @@ can_clk: can {
 		clock-frequency = <0>;
 	};
 
+	/* External PCIe clock - can be overridden by the board */
+	pcie_bus_clk: pcie_bus {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <0>;
+	};
+
 	/* External SCIF clock */
 	scif_clk: scif {
 		compatible = "fixed-clock";