net/mlx5: Remove VLAN insertion fields from WQE Ether segment

Now that the driver no longer uses VLAN TX insertion via the WQE
Ethernet segment, the related fields and flags can be removed.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1757574619-604874-2-git-send-email-tariqt@nvidia.com


Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Leon Romanovsky <leon@kernel.org>