net/mlx5: E-switch, Use eswitch total_vports

Currently steering table and rx group initialization helper
routines works on the total_vports passed as input parameter.

Both eswitch helpers work on the mlx5_eswitch and thereby have access
to esw->total_vports. Hence use it directly instead of passing it
via function input arguments.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Bodong Wang <bodong@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>