net/mlx5: fix E-Switch DV flow disabling

net/mlx5: fix E-Switch DV flow disabling

E-Switch DV flow is supported only when DV flow is supported and
enabled.

The mlx5_shared_dev_ctx_args_config() function ensures that when the
environment does not support DV, the "dv_esw_en" flag is turned off.
However, when the environment is supportive but the user has requested
to disable it, the "dv_esw_en" flag remains on and causes the PMD to try
to create an E-Switch through the Verbs engine.

This patch adds check to ensure that "dv_esw_en" flag will be turned off
when DV flow is disabled.

Fixes: a13ec19c1993 ("net/mlx5: add shared device context config structure")
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>