net: Add ndo_{set|get}_vf_port support for enic dynamic vnics

Add enic ndo_{set|get}_vf_port ops to support setting/getting
port-profile for enic dynamic devices.  Enic dynamic devices are just like
normal enic eth devices except dynamic enics require an extra configuration
step to assign a port-profile identifier to the interface before the
interface is useable.  Once a port-profile is assigned, link comes up on the
interface and is ready for I/O.  The port-profile is used to configure the
network port assigned to the interface.  The network port configuration
includes VLAN membership, QoS policies, and port security settings typical
of a data center network.

A dynamic enic initially has a zero-mac address.  Before a port-profile is
assigned, a valid non-zero unicast mac address should be assign to the
dynamic enic interface.

Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>