Don't set port capabilities for OVS HW offloading

Nova will automatically translate VF capabilities to Neutron
port binding profiles after patch [1] will be merged. Existing
recommendations in "admin/config-ovs-offload.html" should be
updated: there is no need to define capabilities in port
binding profiles for new ports anymore.

[1] https://review.opendev.org/c/openstack/nova/+/899229

Related-bug: #2020813
Depends-on: https://review.opendev.org/c/openstack/nova/+/899229
Change-Id: I63b0641f6b7ef0e1190f421a90619bb2971d0d44
(cherry picked from commit 3fc8d32)
(cherry picked from commit 7daf61a)
(cherry picked from commit ba83353)

Author: MrStupnikov

doc/source/admin/config-ovs-offload.rst

@@ -355,7 +355,7 @@ Validate Open vSwitch hardware offloading
 
    .. code-block:: bash
 
-      # openstack port create --network private --vnic-type=direct --binding-profile '{"capabilities": ["switchdev"]}' direct_port1
+      # openstack port create --network private --vnic-type=direct direct_port1
 
 
 #. Create an instance using the direct port on 'First Compute Node'
@@ -369,7 +369,7 @@ Validate Open vSwitch hardware offloading
 
    .. code-block:: bash
 
-      # openstack port create --network private --vnic-type=direct --binding-profile '{"capabilities": ["switchdev"]}' direct_port2
+      # openstack port create --network private --vnic-type=direct direct_port2
       # openstack server create --flavor m1.small --image mellanox_fedora --nic port-id=direct_port2 vm2
 
    .. note::