cli: add target.memReserve for pci-bridge and pcie-root-port controllers

Libvirt(since v10.3.0) supports setting memReserve attribute to pci-bridge
and pcie-root-port, Let's add it into virt-install. Eg:

virt-install \
......
--controller pci,index=0,model=pcie-root \
--controller pci,index=1,model=pcie-root-port,target.memReserve=8196 \
--controller pci,index=2,model=dmi-to-pci-bridge \
--controller pci,index=3,model=pci-bridge,target.memReserve=8196 \
......

It results in the following domain XML snippet:
    <controller type='pci' index='0' model='pcie-root'>
      <alias name='pcie.0'/>
    </controller>
    <controller type='pci' index='1' model='pcie-root-port'>
      <model name='pcie-root-port'/>
      <target chassis='1' port='0x10' memReserve='8196'/>
      <alias name='pci.1'/>
      <address type='pci' ....../>
    </controller>
    <controller type='pci' index='2' model='dmi-to-pci-bridge'>
      <model name='i82801b11-bridge'/>
      <alias name='pci.2'/>
      <address type='pci' ....../>
    </controller>
    <controller type='pci' index='3' model='pci-bridge'>
      <model name='pci-bridge'/>
      <target chassisNr='3' memReserve='8196'/>
      <alias name='pci.3'/>
      <address type='pci' ....../>
    </controller>

Signed-off-by: Lin Ma <lma@suse.de>

tests/data/cli/compare/virt-install-many-devices.xml

@@ -483,7 +483,7 @@
       <target index="1"/>
     </controller>
     <controller type="pci" index="2" model="pci-bridge">
-      <target chassisNr="1"/>
+      <target chassisNr="1" memReserve="8196"/>
     </controller>
     <controller type="pci" index="3" model="pci-expander-bus">
       <target busNr="252">

tests/test_cli.py

@@ -685,7 +685,7 @@ source.reservations.managed=no,source.reservations.source.type=unix,source.reser
 --controller xenbus,maxGrantFrames=64
 --controller pci,index=0,model=pcie-root-port,target.chassis=1,target.port=1,target.hotplug=off
 --controller pci,index=1,model=pci-root,target.index=1
---controller pci,index=2,model=pci-bridge,target.chassisNr=1
+--controller pci,index=2,model=pci-bridge,target.chassisNr=1,target.memReserve=8196
 --controller pci,index=3,model=pci-expander-bus,target.busNr=252,target.node=1
 --controller usb3
 --controller scsi,model=virtio-scsi

virtinst/cli.py

@@ -4199,6 +4199,7 @@ class ParserController(VirtCLIParser):
         cls.add_arg("target.busNr", "target_busNr")
         cls.add_arg("target.index", "target_index")
         cls.add_arg("target.node", "target_node")
+        cls.add_arg("target.memReserve", "target_memReserve")
 
         cls.add_arg("address", None, lookup_cb=None, cb=cls.set_address_cb)
         cls.add_arg("num_pcie_root_ports", None, lookup_cb=None, cb=cls.noset_cb)

virtinst/devices/controller.py

@@ -85,6 +85,7 @@ class DeviceController(Device):
     target_busNr = XMLProperty("./target/@busNr", is_int=True)
     target_index = XMLProperty("./target/@index", is_int=True)
     target_node = XMLProperty("./target/node", is_int=True)
+    target_memReserve = XMLProperty("./target/@memReserve", is_int=True)
 
     def _get_attached_disk_devices(self, guest):
         ret = []