RDMA/mlx5: Remove pcie_relaxed_ordering_enabled() check for RO write

pcie_relaxed_ordering_enabled() check was added to avoid a syndrome when
creating a MKey with relaxed ordering (RO) enabled when the driver's
relaxed_ordering_{read,write} HCA capabilities are out of sync with FW.

While this can happen with relaxed_ordering_read, it can't happen with
relaxed_ordering_write as it's set if the device supports RO write,
regardless of RO in PCI config space, and thus can't change during
runtime.

Therefore, drop the pcie_relaxed_ordering_enabled() check for
relaxed_ordering_write while keeping it for relaxed_ordering_read.
Doing so will also allow the usage of RO write in VFs and VMs (where RO
in PCI config space is not reported/emulated properly).

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Link: https://lore.kernel.org/r/7e8f55e31572c1702d69cae015a395d3a824a38a.1681131553.git.leon@kernel.org
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>