net/mlx5: fix inline data settings

net/mlx5: fix inline data settings

If the minimal inline data are required the data inline feature
must be engaged. There were the incorrect settings enabling the
entire small packet inline (in size up to 82B) which may result
in sending rate declining if there is no enough cores. The same
problem was raised if inline was enabled to support VLAN tag
insertion by software.

Fixes: 38b4b397a57d ("net/mlx5: add Tx configuration and setup")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>