qemu_domain: Move TPM post parse code into qemuDomainTPMDefPostParse()

qemu_domain: Move TPM post parse code into qemuDomainTPMDefPostParse()

In the qemuDomainDefPostParse() we aim to fill in top level
values, which require overall view of domain, or those parts of
configuration that are not a device in domain XML (e.g. vCPUs).
However, inside of qemuDomainDefTPMsPostParse(), which is called
from aforementioned function, we do two tings:

  1) fill in missing info (TPM version), and
  2) validate TPM definition.

Now, if 1) is moved into qemuDomainTPMDefPostParse() (the device
post parse callback), then 2) can be moved into validation step.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>