dm raid: fix missing reconfig_mutex unlock in raid_ctr() error paths

[ Upstream commit bae30287 ]

In the error paths 'bad_stripe_cache' and 'bad_check_reshape',
'reconfig_mutex' is still held after raid_ctr() returns.

Fixes: 9dbd1aa3

 ("dm raid: add reshaping support to the target")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>