drivers/video/backlight/ld9040.c: use devm_regulator_bulk_get() API

devm_regulator_bulk_get is device managed and saves some cleanup
and exit code.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Donghwa Lee <dh09.lee@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>