Fix checkpatch warning:
WARNING: kfree(NULL) is safe this check is probably not required
Cc: David Woodhouse <dwmw2@infradead.org> Cc: linux-mtd@lists.infradead.org Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Brian Norris <computersforpeace@gmail.com>