netxen: refactor transmit code

o move tx stuff into nx_host_tx_ring structure, this will
  help managing multiple tx rings in future.
o sanitize some variable names

Signed-off-by: Dhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
5 files changed