Merge branch 'net-flower-validate-encapsulation-control-flags'

Asbjørn Sloth Tønnesen says:

====================
net: flower: validate encapsulation control flags

Now that all drivers properly rejects unsupported flower control flags
used with FLOW_DISSECTOR_KEY_CONTROL, then time has come to add similar
checks to the drivers supporting FLOW_DISSECTOR_KEY_ENC_CONTROL.

There are currently just 4 drivers supporting this key, and
3 of those currently doesn't validate encapsulated control flags.

Encapsulation control flags may currently be unused, but they should
still be validated by the drivers, so that drivers will properly
reject any new flags when they are introduced.

This series adds some helper functions, and implements them in all
4 drivers.

NB: It is currently discussed[1] to use encapsulation control flags
for tunnel flags instead of the new FLOW_DISSECTOR_KEY_ENC_FLAGS.

[1] https://lore.kernel.org/netdev/ZmFuxElwZiYJzBkh@dcaratti.users.ipa.redhat.com/
====================

Link: https://lore.kernel.org/r/20240609173358.193178-1-ast@fiberby.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>