common/mlx5: fix relaxed ordering support detection

common/mlx5: fix relaxed ordering support detection

Relaxed ordering is a PCI optimization that allows reordering
of reads/writes in order to improve performance.

In order to enable this optimization only when relaxed ordering
is supported, it is checked if IBV_ACCESS_RELAXED_ORDERING is
defined in verbs.h.

Since IBV_ACCESS_RELAXED_ORDERING is an enum and not
defined relaxed ordering wasn't enabled even when supported.

This issue is fixed by using AUTOCONF to check if relaxed
ordering is supported and disabling only if it isn't.

Fixes: 53ac93f71ad1 ("net/mlx5: create relaxed ordering memory regions")

Signed-off-by: Shiri Kuzin <shirik@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>