KVM: s390: fix locking for crypto setting error path

KVM: s390: fix locking for crypto setting error path

We need to unlock the kvm->lock mutex in the error case.

Reported-by: smatch
Fixes: cb6138e4ef891fae57f ("KVM: s390: device attrs to enable/disable AP interpretation")
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>