staging: octeon-ethernet: drop multiple NAPI instances

Octeon Ethernet driver is currently trying to wake up multiple
CPU cores for parallel NAPI processing when needed, to cope
with the fact that all network interfaces are handled through
the same receive queue processed by a single core/interrupt
(see http://marc.info/?l=linux-kernel&m=137209784914565&w=2

).

This partially overlaps with generic RPS functionality.
Commit a6a39a7f ("staging: octeon-ethernet: disable load balance
for receiving packet when CONFIG_RPS is enabled") already disabled this
when RPS is enabled. Let's delete this code altogether as it has issues
like packet reordering and potential problems with CPU offlining/onlining.

Tested on EdgeRouter Lite.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-By: David Daney <david.daney@cavium.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>