cifs: Use kzfree() to zero out the password

It's safer to zero out the password so that it can never be disclosed.

Fixes: 0c219f5799c7 ("cifs: set domainName when a domain-key is used in multiuser")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

fs/cifs/connect.c

@@ -3101,7 +3101,7 @@ cifs_set_cifscreds(struct smb_vol *vol, struct cifs_ses *ses)
 			rc = -ENOMEM;
 			kfree(vol->username);
 			vol->username = NULL;
-			kfree(vol->password);
+			kzfree(vol->password);
 			vol->password = NULL;
 			goto out_key_put;
 		}