BUG 8880: Trunk port flows not created for subports

BUG 8880: Trunk port flows not created for subports

Fix for BUG 8020 broke the assumption for trunk sub-ports i.e. Interface
will be already created for Subports at time of NeutronPort creation.

https://git.opendaylight.org/gerrit/#/c/54410/ adds an if condition that
will always be false for VM ports, so we don't create interface at Port
creation. This breaks trunk logic. This also has side effect of increasing
rae conditions by adding too much to do once VM is actually spawned and is
not a good design.

Change-Id: I90e5c60f6d5afe5242cdd0a93d5c35d00a25ab85
Signed-off-by: Vishal Thapar <vishal.thapar@ericsson.com>