Merge branch 'mlxsw-SPAN-Support-routes-pointing-at-bridges'

Ido Schimmel says:

====================
mlxsw: SPAN: Support routes pointing at bridges

Petr says:

When mirroring to a gretap or ip6gretap netdevice, the route that
directs the encapsulated packets can reference a bridge. In that case,
in the software model, the packet is switched.

Thus when offloading mirroring like that, take into consideration FDB,
STP, PVID configured at the bridge, and whether that VLAN ID should be
tagged on egress.

Patch #1 introduces functions to get bridge PVID, VLAN flags and to look
up an FDB entry.

Patches #2 and #3 refactor some existing code and introduce a new
accessor function.

With patches #4 and #5 mlxsw calls mlxsw_sp_span_respin() on switchdev
events as well. There is no impact yet, because bridge as an underlay
device is still not allowed.

That is implemented in patch #6, which uses the new interfaces to figure
out on which one port the mirroring should be configured, and whether
the mirrored packets should be VLAN-tagged and how.

Changes from v2 to v3:

- Rename the suite of bridge accessor function to br_vlan_get_pvid(),
  br_vlan_get_info() and br_fdb_find_port(). The _get bit is to avoid
  clashing with an existing static function.

Changes from v1 to v2:

- Change the suite of bridge accessor functions to br_vlan_pvid_rtnl(),
  br_vlan_info_rtnl(), br_fdb_find_port_rtnl().
====================

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