be2net: Bug Fix while accounting of multicast frames during netdev stats update

While updating the statistics to be passed via the get_stats,
tx multicast frames were being accounted instead of rx multicast frames.
This patch fixes the bug. This patch is against the net-2.6 tree.

Signed-off-by: Ajit Khaparde <ajitk@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>