input: route kbd LEDs through the generic LEDs layer

input: route kbd LEDs through the generic LEDs layer

This permits to reassign keyboard LEDs to something else than keyboard
"leds" state, by adding keyboard led and modifier triggers connected to a
series of VT input LEDs, themselves connected to VT input triggers, which
per-input device LEDs use by default.  Userland can thus easily change the
LED behavior of (a priori) all input devices, or of particular input
devices.

This also permits to fix #7063 from userland by using a modifier to
implement proper CapsLock behavior and have the keyboard caps lock led
show that modifier state.

[ebroder@mokafive.com: Rebased to 3.2-rc1 or so, cleaned up some includes, and fixed some constants]
[blogic@openwrt.org: CONFIG_INPUT_LEDS stubs should be static inline]
[akpm@linux-foundation.org: remove unneeded `extern', fix comment layout]
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Evan Broder <evan@ebroder.net>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Bryan Wu <cooloney@gmail.com>
Cc: Arnaud Patard <arnaud.patard@rtp-net.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Matt Sealey <matt@genesi-usa.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Niels de Vos <devos@fedoraproject.org>
Cc: Steev Klimaszewski <steev@genesi-usa.com>
Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>