[Code] working version of ioctl_user and kernel

Now I have just to fix the driver to be usable from user space
following
http://www.makelinux.net/ldd3/chp-3-sect-2
http://stackoverflow.com/questions/21767061/linux-kernel-module-character-device-permissions


Signed-off-by: Francesco Robino <frobino@kth.se>