[PATCH] make leds.h include relevant headers

Make it possible to include linux/leds.h without first including list.h and
spinlock.h.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>