It might be /usr/local/cuda/samples if you have installed the CUDA samples. I’m not sure if you will get these or not, it depends on what apt-get installed, exactly.
If the pcl library is old enough, it may be expecting one of the old CUDA SDK’s to be installed. These can still be downloaded and installed from an older CUDA version (e.g. CUDA 4.2) and then you can still use it (perhaps with some effort) in CUDA 6.5