mtd: nand: atmel: Actually use the PM ops

commit 6e532afa ("mtd: nand: atmel: Add PM ops") was defining PM
ops but nothing was using/referencing those PM ops.

Fixes: 6e532afa ("mtd: nand: atmel: Add PM ops")
Cc: <stable@vger.kernel.org>
Cc: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Wenyou Yang <wenyou.yang@microchip.com>
Tested-by: Romain Izard <romain.izard.pro@gmail.com>