forcedeth: fix tx limit2 flag check

forcedeth: fix tx limit2 flag check

commit 5c659322a904a7cc0265e7b183372b9bdebec6db upstream.

This is a fix for bug 572201 @ bugs.debian.org

This patch fixes the TX_LIMIT feature flag. The previous logic check
for TX_LIMIT2 also took into account a device that only had TX_LIMIT
set.

Reported-by: Stephen Mulcahu <stephen.mulcahy@deri.org>
Reported-by: Ben Huchings <ben@decadent.org.uk>
Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>