tpm: Run swtpm_setup with less parameters on incoming migration

In case of an incoming migration we do not need to run swtpm_setup
with all the parameters but only want to get the benefit of it
creating a TPM state file for us that we can then label with an
SELinux label. The actual state will be overwritten by the in-
coming state. So we have to pass an indicator for incomingMigration
all the way to the command line parameter generation for swtpm_setup.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>