Resubmitting Scott Feldmans original patch with below changes

- Fix port profile strlen which was off by 1
- Added function to convert IFLA_PORT_RESPONSE codes to string

Add support for IFLA_VF_PORTS.  VF port netlink msg layout is

        [IFLA_NUM_VF]
        [IFLA_VF_PORTS]
                [IFLA_VF_PORT]
                        [IFLA_PORT_*], ...
                [IFLA_VF_PORT]
                        [IFLA_PORT_*], ...
                ...
        [IFLA_PORT_SELF]
                [IFLA_PORT_*], ...

The iproute2 cmd line for link set is now:

Usage: ip link add link DEV [ name ] NAME
                   [ txqueuelen PACKETS ]
                   [ address LLADDR ]
                   [ broadcast LLADDR ]
                   [ mtu MTU ]
                   type TYPE [ ARGS ]
       ip link delete DEV type TYPE [ ARGS ]

       ip link set DEVICE [ { up | down } ]
                          [ arp { on | off } ]
                          [ dynamic { on | off } ]
                          [ multicast { on | off } ]
                          [ allmulticast { on | off } ]
                          [ promisc { on | off } ]
                          [ trailers { on | off } ]
                          [ txqueuelen PACKETS ]
                          [ name NEWNAME ]
                          [ address LLADDR ]
                          [ broadcast LLADDR ]
                          [ mtu MTU ]
                          [ netns PID ]
                          [ alias NAME ]
                          [ port MODE { PROFILE | VSI } ]
                          [ vf NUM [ mac LLADDR ]
                                   [ vlan VLANID [ qos VLAN-QOS ] ]
                                   [ rate TXRATE ]
                                   [ port MODE { PROFILE | VSI } ] ]
       ip link show [ DEVICE ]

TYPE := { vlan | veth | vcan | dummy | ifb | macvlan | can }
MODE := { assoc | preassoc | preassocrr | disassoc }
PROFILE := profile PROFILE
           [ instance UUID ]
           [ host UUID ]
VSI := vsi mgr MGRID type VTID ver VER
       [ instance UUID ]
Signed-off-by: Scott Feldman <scofeldm@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>