Merge branch 'mtk_ppe_offload-fixes'

Pablo Neira Ayuso says:

====================
mtk_ppe_offload fixes

A few incremental fixes for the initial flowtable offload support
and this driver:

1) Fix undefined reference to `dsa_port_from_netdev' due to missing
   dependencies in Kconfig, reported by Kbuild robot.

2) Missing mutex to serialize flow events via workqueue to the driver.

3) Handle FLOW_ACTION_VLAN_POP tag action.
====================

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