backlight: cr_bllcd.c: fix a memory leak

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Thomas Hellstrom <thomas@tungstengraphics.com>
Cc: Alan Hourihane <alanh@tungstengraphics.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>