pktgen: NUMA aware

pktgen threads are bound to given CPU, we can allocate memory for
these threads in a NUMA aware way.

After a pktgen session on two threads, we can check flows memory was
allocated on right node, instead of a not related one.

# grep pktgen_thread_write /proc/vmallocinfo
0xffffc90007204000-0xffffc90007385000 1576960 pktgen_thread_write+0x3a4/0x6b0 [pktgen] pages=384 vmalloc N0=384
0xffffc90007386000-0xffffc90007507000 1576960 pktgen_thread_write+0x3a4/0x6b0 [pktgen] pages=384 vmalloc N1=384

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>