net/mlx5: Add merged e-switch cap

When merged e-switch is supported, the per-port e-switch is logically
merged into one e-switch that spans both physical ports and all the VFs.
Under merged eswitch, both the matching on source vport and setting
destination vport can have a 2nd attribute which is the vhca id of the
eswitch owner.

For example:
esw0: {match: <src vport=1 owner=0> action: fwd to <dst vport=7, owner=1>}
is a flow set on eswitch0 matching on source vport=1 from his eswitch
and the action being fwd to dest vport=7 of eswitch1.

Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Shahar Klein <shahark@mellanox.com>
Reviewed-by: Or Gerlitz Klein <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>