arm: dt: zynq: Remove 'clock-ranges' from TTC nodes

The bindings for the TTC changed in commit 'arm: zynq: Use standard
timer binding' (e932900a). That change
removed possible subnodes from this driver rendering the 'clock-ranges'
property invalid for this node.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>