Fix few outdated names of defines:

o NR_REG_SW_NIC -> NR_REG_SW
o NR_RING_NIC_SW -> NR_REG_NIC_SW
o NETMAP_NO_TX_SYNC -> NETMAP_NO_TX_POLL
o NETMAP_DO_RX_SYNC -> NETMAP_DO_RX_POLL

I hope dear luigi has not left those as an excercise to careful
reader, in which case I apologize in advance for ruining his play.

MFC after:     1 week