arm: zynq: Add smp_twd timer

The zynq has a Cortex-A9 with the corresponding smp_twd timers. Use them.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-7000.dtsi

@@ -129,5 +129,12 @@ ttc1: ttc1@f8002000 {
 			clock-names = "cpu_1x";
 			clock-ranges;
 		};
+		scutimer: scutimer@f8f00600 {
+			interrupt-parent = <&intc>;
+			interrupts = < 1 13 0x301 >;
+			compatible = "arm,cortex-a9-twd-timer";
+			reg = < 0xf8f00600 0x20 >;
+			clocks = <&cpu_clk 1>;
+		} ;
 	};
 };