net/mlx5e: SHAMPO, Re-enable HW-GRO

net/mlx5e: SHAMPO, Re-enable HW-GRO

Add back HW-GRO to the reported features.

As the current implementation of HW-GRO uses KSMs with a
specific fixed buffer size (256B) to map its headers buffer,
we reported the feature only if the NIC is supporting KSM and
the minimum value for buffer size is below the requested one.

iperf3 bandwidth comparison:
+---------+--------+--------+-----------+
| streams | SW GRO | HW GRO | Unit      |
|---------+--------+--------+-----------|
| 1       | 36     | 42     | Gbits/sec |
| 4       | 34     | 39     | Gbits/sec |
| 8       | 31     | 35     | Gbits/sec |
+---------+--------+--------+-----------+

A downstream patch will add skb fragment coalescing which will improve
performance considerably.

Benchmark details:
VM based setup
CPU: Intel(R) Xeon(R) Platinum 8380 CPU, 24 cores
NIC: ConnectX-7 100GbE
iperf3 and irq running on same CPU over a single receive queue

Signed-off-by: Yoray Zack <[email protected]>
Signed-off-by: Tariq Toukan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>