Add a second set of global states, "rfkill_default_states", to track the
state that will be used when the first rfkill class of a given type is
registered, and also to save "undo" information when rfkill_epo is called.

Add a new exported function, rfkill_set_default(), which can be used by
platform drivers to restore radio state saved by the platform across
reboots or shutdown.

Also, fix rfkill_epo to properly update rfkill_states, but still preserve a
copy of the state so that we can undo the effect of rfkill_epo later if we
want to.  Add rfkill_restore_states() to restore rfkill_states from the
copy.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

SW_RFKILL_ALL is the "emergency power-off all radios" input event.  It must
be handled, and must always do the same thing as far as the rfkill system
is concerned: all transmitters are to go *immediately* offline.

For safety, do NOT allow userspace to override EV_SW SW_RFKILL_ALL OFF.  As
long as rfkill-input is loaded, that event will *always* be processed, and
it will *always* force all rfkill switches to disable all wireless
transmitters, regardless of user_claim attribute or anything else.
Signed-off-by: NHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: NIvo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

rfkill_switch_all shouldn't be called by drivers directly,
instead they should send a signal over the input device.

To prevent confusion for driver developers, move the
function into a rfkill private header.
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>