Description of problem:
While vm(without vtpm) running, tick 'TPM Device Enabled', ok. 'Changes that require vm restart' shows, but later check 'edit' again, the checkbox is still empty. Poweroff and run vm again, still no vtpm added.

Version-Release number of selected component (if applicable):
ovirt-engine-4.4.6.1-0.11.el8ev.noarch
vdsm-4.40.60.2-1.el8ev.x86_64
libvirt-7.0.0-13.module+el8.4.0+10604+5608c2b4.x86_64
qemu-kvm-5.2.0-14.module+el8.4.0+10425+ad586fa5.x86_64

How reproducible:
100%

Steps to Reproduce:
1. In uefi cluster, run a vm without vtpm

2. Edit vm to enable tpm device (to use it next start).

3. Check tpm dev status by edit again.

4. Restart vm to check vtpm.


Actual results:
In step2, 'Changes that require vm restart' shows, but in step3, the checkbox is still empty.
In step4, the vm still has no vtpm added.

Expected results:
The tpm device enabling should be saved, and take effect next time.
Or give tips and forbid this action.

Additional info:
Not reproduces if add tpm when vm shutoff.