mlxsw: spectrum_acl: Fix mlxsw_sp_acl_tcam_group_add()'s error path

If mlxsw_sp_acl_tcam_group_id_get() fails, the mutex initialized earlier
is not destroyed.

Fix this by initializing the mutex after calling the function. This is
symmetric to mlxsw_sp_acl_tcam_group_del().

Fixes: 5ec2ee28d2 ("mlxsw: spectrum_acl: Introduce a mutex to guard region list updates")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c

@@ -292,13 +292,14 @@ mlxsw_sp_acl_tcam_group_add(struct mlxsw_sp_acl_tcam *tcam,
 	int err;
 
 	group->tcam = tcam;
-	mutex_init(&group->lock);
 	INIT_LIST_HEAD(&group->region_list);
 
 	err = mlxsw_sp_acl_tcam_group_id_get(tcam, &group->id);
 	if (err)
 		return err;
 
+	mutex_init(&group->lock);
+
 	return 0;
 }