net: libwx: fix multicast packets received count

net: libwx: fix multicast packets received count

Multicast good packets received by PF rings that pass ethternet MAC
address filtering are counted for rtnl_link_stats64.multicast. The
counter is not cleared on read. Fix the duplicate counting on updating
statistics.

Fixes: 46b92e10d631 ("net: libwx: support hardware statistics")
Cc: stable@vger.kernel.org
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/DA229A4F58B70E51+20250714015656.91772-1-jiawenwu@trustnetic.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>