Description of problem:
memlock limit increase even the hotplug is not succeed when there is a vdpa interface

Version-Release number of selected component (if applicable):
libvirt-9.0.0-7.el9.x86_64

How reproducible:
100%

Steps to Reproduce:
1.  start vm with 2G memory and a vdpa interface;# virsh dumpxml rhel <memory unit='KiB'>2097152</memory>
  <currentMemory unit='KiB'>2097152</currentMemory>
...  
<interface type="vdpa">
  <mac address="00:11:22:33:44:00"/>
  <source dev="/dev/vhost-vdpa-0"/>
  <model type="virtio"/>
  <alias name="ua-test"/>
  <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
</interface>

1. virsh start rhel
   Domain 'rhel' started

2. check the memlock limit, it's 3G, which is as expected:# prlimit  -p `pidof qemu-kvm` | grep MEMLOCK
MEMLOCK    max locked-in-memory address space 3221225472 3221225472 bytes

3. prepare a hostdev device xml which is not in a separate iommu group: # cat device.xml
<hostdev mode='subsystem' type='pci' managed='yes'>
    <source>
      <address domain='0x0000' bus='0x04' slot='0x00' function='0x1'/>
    </source>
  </hostdev>

1. virsh nodedev-dumpxml pci_0000_04_00_0  --xpath  //iommuGroup
   <iommuGroup number="14">
     <address domain="0x0000" bus="0x04" slot="0x00" function="0x1"/>
     <address domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
   </iommuGroup>

3. try to hotplug the device, then check the memlock limit is updated:# virsh attach-device rhel device.xml  
error: Failed to attach device from device.xml
error: internal error: unable to execute QEMU command 'device_add': vfio 0000:04:00.1: group 14 is not viable

1. prlimit  -p `pidof qemu-kvm` | grep MEMLOCK
   MEMLOCK    max locked-in-memory address space 5368709120 5368709120 bytes
   Actual results:
   In step 3, the memlock limit increase even the hotplug is not succeed

Expected results:
In step 3, the memlock limit should not be updated since the hotplug is not succeed

Additional info:
1). If no vdpa interface exists in the vm, the memlock limit will not increase, which is as expected;# virsh attach-device rhel device1.xml
error: Failed to attach device from device1.xml
error: internal error: unable to execute QEMU command 'device_add': vfio 0000:19:00.1: group 29 is not viable

1. prlimit  -p  `pidof qemu-kvm` | grep MEMLOCK
   MEMLOCK    max locked-in-memory address space  67108864  67108864 bytes

2). No such issue for hotplug with other reasons like:a. the device is occupied by other domain:# virsh attach-interface rhel  hostdev --managed 0000:3b:0a.0
error: Failed to attach interface
error: Requested operation is not valid: PCI device 0000:3b:0a.0 is in use by driver QEMU, domain test

1. prlimit  -p  8662  | grep MEMLOCK
   MEMLOCK    max locked-in-memory address space  67108864  67108864 bytesb. do not enable iommu:# virsh attach-interface rhel hostdev --managed 0000:3b:0a.0
   error: Failed to attach interface
   error: unsupported configuration: host doesn't support passthrough of host PCI devices
2. prlimit  -p  `pidof qemu-kvm`  | grep MEMLOCK
   MEMLOCK    max locked-in-memory address space  67108864  67108864 bytes