set_nsp and set_nsi action NX support

Sample output from OVS:
[madhu@localhost ~]# sudo ovs-ofctl dump-flows br-int -O OpenFlow13
OFPST_FLOW reply (OF1.3) (xid=0x2):
 cookie=0x0, duration=20.337s, table=1, n_packets=0, n_bytes=0, send_flow_rem ip,nw_dst=1.1.1.1 actions=set_nsp:0x3e8,set_nsi:45

Change-Id: Ie533ed3eaca7f032a36bf19230a22004d75db424
Signed-off-by: Madhu Venugopal <mavenugo@gmail.com>
Added utility methods for set_nsp and set_nsi actions.

Change-Id: Ic6cb8725f394251eb6f89e95e5ee8d9428468e62
Signed-off-by: Madhu Venugopal <mavenugo@gmail.com>
Merge changes Ic6cb8725,Ie533ed3e

* changes:
  Added utility methods for set_nsp and set_nsi actions.
  set_nsp and set_nsi action NX support