rionet: fix page allocation order of rionet_active

rionet_active is allocated from the page allocator and the allocation
order is calculated on the assumption that the page size is 4KB, so it
wastes memory on more than 4K page systems.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>