cgminer doesn't support any clock features on Cairnsmore1
We've never had the hardware (and none of the other Icarus I have: an original Icarus, a Black Arrow Lancelot and a Asicminer USB, have miner programmable clocking)
As I've mentioned before and long ago, if someone has one they want to send me, I'll be able to add support for that.

I did write the original --icarus-options code to support other Icarus bitstream devices with varying FPGA configurations (the code that is in cgminer and the clone) and could test that on a normal icarus with the correct settings for a normal Icarus.
But obviously can't write and test the clocking code without one.

At the moment I've been trying to track down someone with one to simply compile and run a binary and get me certain output rather than removing Cairnsmore1 from the next version (i.e. trying to at least have basic Icarus settings support)
I've had a few offers, but since the 1st one couldn't, I'll try the next shortly.