be2net: post buffers before destroying RXQs in Lancer

An RX stall issue was seen on Lancer adapters, when RXQs are destroyed
while they are in an "out of buffer" state. This patch fixes this issue
by posting 64 buffers to each RXQ before destroying them in the close path.
This is done after ensuring that no more new packets are selected for
transfer to the RXQs by disabling interface filters.

Signed-off-by: Kalesh AP <kalesh.purayil@avagotech.com>
Signed-off-by: Sathya Perla <sathya.perla@avagotech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>