net/mlx5e: Tx, Enforce L4 inline copy when needed

When ctrl->tisn field exists, this indicates an operation (HW offload)
on the TCP payload.
For such WQEs, inline the headers up to L4.

This is in preparation for kTLS HW offload support, added in
a downstream patch.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>