Description of problem:
Unify whether virtio console can accept 'virtio-serial' address

Version-Release number of selected component (if applicable):
libvirt-4.3.0-1.el8+732+cd548b25.x86_64
kernel-4.17.0-6.el8+7.x86_64
qemu-kvm-2.12.0-13.el8+812+c321fc4d.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Edit VM with the following consiguration and then start VM
# virsh edit vm1
    <console type='pty' tty='/dev/pts/5'>
      <source path='/dev/pts/5'/>
      <target type='virtio' port='0'/>
      <alias name='console0'/>
    </console>
    <console type='pty'>
      <source path='/dev/pts/8'/>
      <target type='virtio' port='1'/>
      <alias name='console1'/>
      <address type='virtio-serial' controller='0' bus='0' port='3'/>
    </console>

# virsh start vm1
Domain vm1 started

# virsh dumpxml vm1 |grep "<console" -A30
    <console type='pty' tty='/dev/pts/5'>
      <source path='/dev/pts/5'/>
      <target type='virtio' port='0'/>
      <alias name='console0'/>
    </console>
    <console type='pty'>
      <source path='/dev/pts/8'/>
      <target type='virtio' port='1'/>
      <alias name='console1'/>
      <address type='virtio-serial' controller='0' bus='0' port='3'/>
    </console>

Actual results:
As step-1 shows

Expected results:
If console can not accept virtio-serial address, then VM should start failed.
IF console can accept, then the other console device should generate address, too.

Additional info: