sony-laptop: Add rfkill support on new models

Newer Vaios provide a full featured rfkill implementation via their
platform methods. Add support for enumerating the available devices and
providing rfkill access to them. Support for the physical kill switch is
added, with the devices moving into the HARD_BLOCKED state when toggled.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Len Brown <len.brown@intel.com>