net/mlx5e: Add TC HW support for FDB (SRIOV e-switch) offloads

Enhance the TC offload code such that when the eswitch exists and it's
mode being SRIOV offloads, we do TC actions parsing and setup targeted
for eswitch. Next, we add the offloaded flow to the HW e-switch (fdb).

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>