cgminer doesn't detect GPU in ssh session
The reason for this is that the X-Server that is handling the GPUs is not available in the SSH session. Try prefixing all commands with DISPLAY=:0. This tells cgminer which X-Server instance to use. The cgminer command then simply becomes:

DISPLAY=:0 ./cgminer -u ...


You can also fix this for the current session with the following

export DISPLAY=:0


this defines the variable in a bash shell (see your shell's documentation for details if you're using another shell). Putting this into your .bashrc file might be a good idea if you intend to use it only over SSH .