Combine the "command" and "completion" locks into a single lock,
on each egress queue, to improve efficiency.

Support the use of 4KB pages in the "egress queue".

Delete the unused "duplicate ACK compression" code.

Filter "bad" (i.e. truncated) packets.

Avoid corrupting "dev->napi_list", by sequentializing modifications.

Deregister for incoming packets during stop, to reduce unexpected
interrupts.  Also, encourage active NAPI loops to complete before
we disable NAPI, which would otherwise crash.

Free any pending completions after shutting down LEPP.

Use a single, permanently registered, IRQ handler, to avoid situations
in which the IRQ handler was firing after being freed, and ignore any
"unexpected" interrupts.

Drop egress packets, instead of spinning, if the hardware cannot keep
up, or is disconnected.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>