linux-imx

mtd: Fix check in mtd_unpoint()

The code checks that ->_point is not NULL, but we should actually check
->_unpoint value which is dereferenced a few lines after the check.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>