pull skb data in cil_from_netdev path for HIGH_SCALE_IPCACHE mode

[sofat1989]

Now we enabled the high scale ipcache mode. And on some nodes with Mellanox nic cards, we found that cilium dropped the icmp packets for path MTU discovery. So the packets will be dropped when the clients send huge packets.

/# lspci | grep -i Mellanox
1f:00.0 Ethernet controller: Mellanox Technologies MT27520 Family [ConnectX-3 Pro]

xx drop (Invalid packet) flow 0xb18ed4da to endpoint 0, ifindex 4, file 1:1061, , identity unknown->unknown: 10.* -> 10.2* DestinationUnreachable(FragmentationNeeded)

fix bug: pull skb data in cil_from_netdev path for HIGH_SCALE_IPCACHE mode

[julianwiedmann]

/test

[julianwiedmann]

(I dropped the Fixes: reference to #12854 from the description, as this bug is unrelated to that old issue)