Merge branch 'Mirroring-tests-involving-VLAN'

Petr Machata says:

====================
Mirroring tests involving VLAN

This patchset tests mirror-to-gretap with various underlay
configurations involving VLAN netdevice in particular. Some of the tests
involve bridges as well, but tests aimed specifically at testing bridges
(i.e. FDB, STP) are not part of this patchset.

In patches #1-#6, the codebase is adapted to support the new tests.

In patch #7, a test for mirroring to VLAN is introduced.

Patches #8-#10 add three tests where VLAN is part of underlay path after
gretap encapsulation.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>