fixed-clock: First revision

Dummy object inheriting from Device for a fixed frequency clock.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
zynq-pll: First revision

Dummy object inheriting from Device for the zynq PLL.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>