Staging: Octeon Ethernet: Rewrite transmit code.

Stop the queue if too many packets are queued.  Restart it from a high
resolution timer.

Rearrange and simplify locking and SKB freeing code

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: gregkh@suse.de
Patchwork: http://patchwork.linux-mips.org/patch/843/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>