Add a note that UEFI VMs using TPM devices should be configured
to use a varfile. Some UEFI boot loaders, such as shim, update
persistent boot variables and then reset the system when a TPM is
present. Without a writable varfile, the VM may be reset repeatedly.
Add a TPM device example to the examples list.
While here, add a missing "\" to the "uefivm" example, and add ".Pp"
before the vCPU pinning examples for consistency with other examples.
PR: 287326
MFC after: 3 days