I'm going to throw schedule_work away, it's retarded. But for starters,
let's have it encapsulated.

Also, generic and whiteheat were both calling usb_serial_port_softint
and scheduled work. Only one was necessary.
Signed-off-by: NPete Zaitcev <zaitcev@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>