net/mlx5e: fix a potential double-free in fs_any_create_groups

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: fix a potential double-free in fs_any_create_groups When kcalloc() for ft->g succeeds but kvzalloc() for in fails, fs_any_create_groups() will free ft->g. However, its caller fs_any_create_table() will free ft->g again through calling mlx5e_destroy_flow_table(), which will lead to a double-free. Fix this by setting ft->g to NULL in fs_any_create_groups().