Add trunk subports to be one of dvr serviced device owners

When "trunk:subport" wasn't added to the list of device owners which
are supported by dvr, there was no proper config in br-int's openflow
rules for such port, e.g. there was no dvr_to_src_mac rule in table 1
added and traffic from such port was never going through br-int.

Trunk ports should be added to this dvr serviced device owners list and
that patch is adding it there.

Conflicts:
    neutron/common/utils.py

Change-Id: Ic21089adfa32dbf5d0e29a89713e6e2bf28f0f05
Closes-Bug: #1870114
(cherry picked from commit d0a1652227)

neutron/common/utils.py

@@ -46,6 +46,7 @@ import neutron
 from neutron._i18n import _
 from neutron.api import api_common
 from neutron.db import api as db_api
+from neutron.services.trunk import constants as trunk_constants
 
 TIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
 LOG = logging.getLogger(__name__)
@@ -169,7 +170,8 @@ def get_other_dvr_serviced_device_owners(host_dvr_for_dhcp=True):
     separately (see is_dvr_serviced() below)
     """
     device_owners = [n_const.DEVICE_OWNER_LOADBALANCER,
-                     n_const.DEVICE_OWNER_LOADBALANCERV2]
+                     n_const.DEVICE_OWNER_LOADBALANCERV2,
+                     trunk_constants.TRUNK_SUBPORT_OWNER]
     if host_dvr_for_dhcp:
         device_owners.append(n_const.DEVICE_OWNER_DHCP)
     return device_owners