linux-phytec-ti

sony-laptop: add support for more WWAN modems

Also make the initialization function return a value for consistency
with all the other setup functions.

Signed-off-by: Marco Chiappero <marco@absence.it>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <mjg@redhat.com>