packet: doc: describe PACKET_MMAP with one packet socket for rx and tx
packet: doc: describe PACKET_MMAP with one packet socket for rx and tx

Document how to use one AF_PACKET mmap socket for RX and TX.

Signed-off-by: Norbert van Bolhuis <0111b822afbabce8a3aa6ef0a4de3c7f2e3193a9@aimvalley.nl>
Signed-off-by: Daniel Borkmann <9ff04a02a69f376b2b9aeec27187017cbf3cf5f9@redhat.com>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs