Flow offloaded conntrack entries carry no timeout value and trip up the
record parsing routine. Adjust the code to properly deal with such entries.
Ref: https://forum.openwrt.org/t/offloading-breaks-connections-list/126423
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
(cherry picked from commit 531c0ecff2ca57c4bc0aacee66a0746814fefc78)