qemu_tpm: Do not use persistent definition during pre-start checks

qemu_tpm: Do not use persistent definition during pre-start checks

Commit 3451987fca7c used the persistent TPM Definition in both calls to
qemuTPMVirCommandSwtpmAddTPMState() but in one of the two cases it
might've been NULL and what's more, it is not the right definition which
should've been used.  Change that to @tpm which is the current
definition.  The other call does not have access to the current
definition and is only called during updating the profile.  But for the
sake of fewer future mistakes, keep the other one as is because there is
no issue with calling it that way and adding logic that just skips the
extra check on NULL could mistake someone in the future.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>