tpm: tpm-tis-device: set PPI to false by default

tpm: tpm-tis-device: set PPI to false by default

The tpm-tis-device device does not support PPI. Let's
change the default value for the corresponding property
instead of tricking this latter in the mach-virt machine.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Message-id: 20200427143145.16251-2-eric.auger@redhat.com