ARM: zynq: add clk binding support to the ttc

Add support for retrieving TTC configuration from device tree.  This
includes the ability to pull information about the driving clocks from
the of_clk bindings.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-zc702.dts

@@ -32,3 +32,13 @@
 &ps_clk {
 	clock-frequency = <33333330>;
 };
+
+&ttc0_0 {
+	status = "ok";
+	compatible = "xlnx,ttc-counter-clocksource";
+};
+
+&ttc0_1 {
+	status = "ok";
+	compatible = "xlnx,ttc-counter-clockevent";
+};