staging: et131x: Remove et131x_send_packets() function

Remove et131x_send_packets() and replace the only use in et131x_tx
with the removed function's body.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: In et131x_tx(), don't return NETDEV_TX_BUSY, just drop the packet

Memory allocation errors do not denote NETDEV_TX_BUSY, simply drop
the packet silently with kfree_skb() and return NETDEV_TX_OK.

Also remove this item from the TODO list.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Tidy up rx/tx dropped & bytes stats

Remove some fairly useless comments regarding rx/tx _bytes and
_dropped, and use rcvd_pkts_dropped stat value to provide rx_dropped.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Remove ununsed statistics

From struct ce_stats; unicast_pkts_rcvd, unicast_pkts_xmtd,
multicast_pkts_xmtd, broadcast_pkts_rcvd and broadcast_pkts_xmtd
are not returned or used for anything meaningful - remove the code
that collects them, and the struct members too.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Remove struct tcb->flags

'struct tcb' member 'flags' was only used to collect tx stats, now
we are no longer collecting those particular stats, we no longer
need tcb->flags or the code used to peek into the skb to set it's
value.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Combine two if statements with same effect

Both these if statements have the same effect when true, so combine
them and save a few lines.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Simplify code in nic_rx_pkts() for multicast_pkts_rcvd

In nic_rx_pkts(), we check that a multicast packet received (when using
a multicast list) is one that was requested - despite setting the list
up with the hardware. We shouldn't expect to get a mc packet we didn't
ask for, so remove these extra checks.

This also means that the surrounding code can be tiedied up a little.

Tested somewhat with omping, with no adverse effects seen.

Also remove this item from the TODO list.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
staging: et131x: Remove 'reduce number of spinlocks' TODO item

The number of spinlocks has been halved, from 8 to 4 since this
comment was made, let's see if this is enough.

Signed-off-by: Mark Einon <mark.einon@gmail.com>