[MTD] [NOR] Support for auto locking flash on power up

Auto unlock sectors on resume for auto locking flash on power up.

Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>