net/mlx5e: Fix memleak in mlx5e_create_l2_table_groups

stable inclusion
from linux-4.19.168
commit 778e1171b4dccd6706e2b8717379c4dd675149be

--------------------------------

commit 5b0bb12c upstream.

When mlx5_create_flow_group() fails, ft->g should be
freed just like when kvzalloc() fails. The caller of
mlx5e_create_l2_table_groups() does not catch this
issue on failure, which leads to memleak.

Fixes: 33cfaaa8 ("net/mlx5e: Split the main flow steering table")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Signed-off-by: Aichun Li <liaichun@huawei.com>
reviewed-by: wangxiaopeng <wangxiaopeng7@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>