Fixes coccicheck warning:

drivers/md/dm-bio-prison-v2.c:327:2-22: WARNING: Assignment of 0/1 to bool variable
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: Nzhengbin <zhengbin13@huawei.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>