Merge branch 'net-gro-fix-outer-network-offset'

Paolo Abeni says:

====================
net: gro: fix outer network offset

The GRO stage has still problems in some edge scenarios when dealing
with encapsulated traffic: the first patch address an issue there
leading to bad checksums.

The second patch introduces a test case covering the relevant scenario:
S/W segmentation after GRO for encapsulated traffic.
====================

Link: https://patch.msgid.link/cover.1770032084.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>