net/mlx5e: Query minimum required header copy during xmit

Add support for query the minimum inline mode from the Firmware.
It is required for correct TX steering according to L3/L4 packet
headers.

Each send queue (SQ) has inline mode that defines the minimal required
headers that needs to be copied into the SQ WQE.
The driver asks the Firmware for the wqe_inline_mode device capability
value.  In case the device capability defined as "vport context" the
driver must check the reported min inline mode from the vport context
before creating its SQs.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>