cifs: Use kzfree() to free password

We should zero out the password before we free it.

Fixes: 3d6cacbb5310 ("cifs: Add DFS cache routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>

fs/cifs/dfs_cache.c

@@ -1127,7 +1127,7 @@ static int dup_vol(struct smb_vol *vol, struct smb_vol *new)
 err_free_unc:
 	kfree(new->UNC);
 err_free_password:
-	kfree(new->password);
+	kzfree(new->password);
 err_free_username:
 	kfree(new->username);
 	kfree(new);