s2io: add dynamic LRO disable support

This patch adds dynamic LRO disable support for s2io net driver,
enables LRO by default, increases the driver version number, and
corrects the name of the LRO modparm.

This is mostly Wang's patch based on Neil's initial work, heavily
modified based on Ramkrishna's suggestions.  This has been tested on
a Neterion Xframe adapter and verified via adapter LRO statistics.

Signed-off-by: Jon Mason <jon.mason@exar.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Neil Horman <nhorman@redhat.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Ramkrishna Vepa <Ramkrishna.Vepa@exar.com>
Signed-off-by: David S. Miller <davem@davemloft.net>