leds: leds-pca9532 cleanups

- Remove unneeded input_free_device() after input_unregister_device().

- Add pca9532_destroy_devices() function for destroy devices.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>