net/mlx5: Use order-0 allocations for all WQ types

Complete the transition of all WQ types to use fragmented
order-0 coherent memory instead of high-order allocations.

CQ-WQ already uses order-0.
Here we do the same for cyclic and linked-list WQs.

This allows the driver to load cleanly on systems with a highly
fragmented coherent memory.

Performance tests:
ConnectX-5 100Gbps, CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz
Packet rate of 64B packets, single transmit ring, size 8K.

No degradation is sensed.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>