[ Upstream commit e3fc3f3d ]

The first argument to WARN() is supposed to be a condition.  The
original code will just print the mdname() instead of the full warning
message.

Fixes: c84a1372 ("md/raid0: avoid RAID0 data corruption due to layout confusion.")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>