drivers/input/input.c: fix CONFIG_PM=n warning

drivers/input/input.c:1277: warning: 'input_dev_reset' defined but not used

Acked-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>