net/mlx5e: tc, Refactor peer add/del flow

Move peer_eswitch outside mlx5e_tc_add_fdb_peer_flow() so downstream
patch can call mlx5e_tc_add_fdb_peer_flow() with multiple peers.
Move peer_eswitch in the remove flow as well in order to keep symmetry.

Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>