add patch for igc tx timeout issue

add patch for igc tx timeout issue

There were several reports about issues related to igc and tx timeout
and while the issue couldn't be reproduced locally, the hope is that
this fix Friedrich found will resolve the issue for the users. The
kernel versions in the reports would match with when 9b275176270e
("igc: Add ndo_tx_timeout support"), i.e. the one fixed by this
commit, landed.

[0]: https://forum.proxmox.com/threads/130935/
[1]: https://forum.proxmox.com/threads/130415/#post-580064
[2]: https://forum.proxmox.com/threads/132138/

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>