net/mlx5: Refactor mlx5_create_auto_grouped_flow_table

Refactor mlx5_create_auto_grouped_flow_table() to use ft_attr param
which already carries the max_fte, prio and flags memebers, and is
used the same in similar mlx5_create_flow_table() function.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>