backlight: atmel-pwm-bl: fix gpio polarity in remove

commit ad5066d4c2b1d696749f8d7816357c23b648c4d3 upstream.

Make sure to honour gpio polarity also at remove so that the backlight is
actually disabled on boards with active-low enable pin.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Qiang Huang <h.huangqiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>