ARM: shmobile: sh73a0 dtsi: Add Cortex-A9 TWD node

Add a node for the Private Timer and Watchdog, as found in the Cortex-A9
MPCore.

Without this, there's no clocksource available during early kernel
initialization, before cmt1 is initialized, leading to a lock-up if
CONFIG_CPU_IDLE=y.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/sh73a0.dtsi

@@ -11,6 +11,7 @@
 /include/ "skeleton.dtsi"
 
 #include <dt-bindings/clock/sh73a0-clock.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
 #include <dt-bindings/interrupt-controller/irq.h>
 
 / {
@@ -35,6 +36,13 @@ cpu@1 {
 		};
 	};
 
+	timer@f0000600 {
+		compatible = "arm,cortex-a9-twd-timer";
+		reg = <0xf0000600 0x20>;
+		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_HIGH)>;
+		clocks = <&twd_clk>;
+	};
+
 	gic: interrupt-controller@f0001000 {
 		compatible = "arm,cortex-a9-gic";
 		#interrupt-cells = <3>;