Geometry needs to be qdev properties, because it belongs to the
disk's guest part.

Maintain backward compatibility exactly like for serial: fall back to
DriveInfo's geometry, set with -drive cyls=...

Bonus: info qtree now shows the geometry.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>