Make version 1.2 compile and run on linux 3.2

I made the master version also compile and run on linux 3.2.

I tested it quickly and it works, seemingly fine. My doubts are about removing the calls: tty_port_link_device and tty_port_destroy. They are not available on kernels below 3.7 and I don't see how to correctly substitute them. Do you know if just removing them is the right thing to do?