Use the notification chains to also send uevents, so that userspace can be
notified of state changes of every rfkill switch.

Userspace should use these events for OSD/status report applications and
rfkill GUI frontends.  HAL might want to broadcast them over DBUS, for
example.  It might be also useful for userspace implementations of
rfkill-input, or to use HAL as the platform driver which promotes rfkill
switch change events into input events (to synchronize all other switches)
when necessary for platforms that lack a convenient platform-specific
kernel module to do it.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>