drivers/leds/leds-bd2802.c: bd2802_unregister_led_classdev() should unregister all registered leds

bd2802_unregister_led_classdev() should unregister all registered
instances of led_classdev class that had registered by
bd2802_register_led_classdev().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Kim Kyuwon <q1.kim@samsung.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>