avf: Support interrupt mode

avf: Support interrupt mode

DBGvpp# set interface rx-mode AVF0/4/2/0 interrupt
set interface rx-mode AVF0/4/2/0 interrupt
DBGvpp# sh int rx
sh int rx
Thread 0 (vpp_main):
  node dpdk-input:
    FortyGigabitEthernet6/0/0 queue 0 (polling)
  node avf-input:
    AVF0/4/2/0 queue 0 (interrupt)
DBGvpp# sh int addr
sh int addr
AVF0/4/2/0 (up):
  L3 133.1.1.10/24
FortyGigabitEthernet6/0/0 (dn):
VirtualEthernet0/0/0 (up):
  L3 192.168.42.1/24
DBGvpp# clear run
clear run
DBGvpp# clear interfaces
clear interfaces
DBGvpp# sh int rx
sh int rx
Thread 0 (vpp_main):
  node dpdk-input:
    FortyGigabitEthernet6/0/0 queue 0 (polling)
  node avf-input:
    AVF0/4/2/0 queue 0 (interrupt)
DBGvpp# ping 133.1.1.3 repeat 1
ping 133.1.1.3 repeat 1
64 bytes from 133.1.1.3: icmp_seq=1 ttl=64 time=.6237 ms

Statistics: 1 sent, 1 received, 0% packet loss
DBGvpp# sh int
sh int
              Name               Idx    State  MTU (L3/IP4/IP6/MPLS)     Counter          Count
AVF0/4/2/0                        5      up          9000/0/0/0     rx packets                     1
                                                                    rx bytes                      98
                                                                    tx packets                     1
                                                                    tx bytes                      98
                                                                    drops                          1
                                                                    ip4                            1
FortyGigabitEthernet6/0/0         1     down         9000/0/0/0
VirtualEthernet0/0/0              2      up          9000/0/0/0
local0                            0     down         9000/0/0/0
DBGvpp# sh run
sh run
Time 41.9, average vectors/node 1.00, last 128 main loops 0.00 per node 0.00
  vector rates in 2.3858e-2, out 2.3858e-2, drop 2.3858e-2, punt 0.0000e0
             Name                 State         Calls          Vectors        Suspends         Clocks       Vectors/Call
AVF0/4/2/0-output                active                  1               1               0          1.24e4            1.00
AVF0/4/2/0-tx                    active                  1               1               0          4.28e4            1.00
api-rx-from-ring                any wait                 0               0               2          6.94e4            0.00
avf-input                     interrupt wa               1               1               0          1.09e4            1.00
avf-process                     any wait                 0               0              47          1.01e4            0.00
...
DBGvpp#
DBGvpp# set interface rx-mode AVF0/4/2/0 polling
set interface rx-mode AVF0/4/2/0 polling
DBGvpp# sh int rx
sh int rx
Thread 0 (vpp_main):
  node dpdk-input:
    FortyGigabitEthernet6/0/0 queue 0 (polling)
  node avf-input:
    AVF0/4/2/0 queue 0 (polling)
DBGvpp# ping 133.1.1.3 repeat 1
ping 133.1.1.3 repeat 1
64 bytes from 133.1.1.3: icmp_seq=1 ttl=64 time=.2038 ms

Statistics: 1 sent, 1 received, 0% packet loss
DBGvpp#

Change-Id: Ib7d2b505ae4bb74a052263af766ca37d9df7bfe4
Signed-off-by: Steven <sluong@cisco.com>