Merge branch 'ip6gre-tests'

Ido Schimmel says:

====================
selftests: forwarding: Add ip6gre tests

This patchset adds forwarding selftests for ip6gre. The tests can be run
with veth pairs or with physical loopbacks.

Patch #1 adds a new config option to determine if 'skip_sw' / 'skip_hw'
flags are used when installing tc filters. By default, it is not set
which means the flags are not used. 'skip_sw' is useful to ensure
traffic is forwarded by the hardware data path.

Patch #2 adds a new helper function.

Patches #3-#4 add the forwarding selftests.

Patch #5 adds a mlxsw-specific selftest to validate correct behavior of
the 'decap_error' trap with IPv6 underlay.

Patches #6-#8 align the corresponding IPv4 underlay test to the IPv6
one.
====================

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