net/mlx5e: Move Ethernet driver debugfs to profile init callback

As priv->dfs_root is cleared, and therefore missed, when change
eswitch mode, move the creation of the root debugfs to the init
callback of mlx5e_nic_profile and mlx5e_uplink_rep_profile, and
the destruction to the cleanup callback for symmeter.

Fixes: 288eca60

 ("net/mlx5e: Add Ethernet driver debugfs")
Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>