drivers/video/backlight/ltv350qv.c: fix a memory leak

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.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>