net/mlx5e: fix double free in mlx5e_destroy_flow_table

In function accel_fs_tcp_create_groups(), when the ft->g memory is
successfully allocated but the 'in' memory fails to be allocated, the
memory pointed to by ft->g is released once. And in function
accel_fs_tcp_create_table, mlx5e_destroy_flow_table is called to release
the memory pointed to by ft->g again. This will cause double free problem.

Fixes: c062d52a ("net/mlx5e: Receive flow steering framework for accelerated TCP flows")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>