net/mlx5_core: Modify arm CQ in preparation for upcoming Ethernet driver

Pass consumer index as a parameter to arm CQ

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>