hw/i386/pc_piix: Mark the machine types from version 1.4 to 1.7 as deprecated

hw/i386/pc_piix: Mark the machine types from version 1.4 to 1.7 as deprecated

The list of machine types grows larger and larger each release ... and
it is unlikely that many people still use the very old ones for live
migration. QEMU v1.7 has been released more than 8 years ago, so most
people should have updated their machines to a newer version in those
8 years at least once. Thus let's mark the very old 1.x machine types
as deprecated now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220117191639.278497-1-thuth@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>