ACPI / video: Thinkpad X201 Tablet needs video_detect_force_video

Add Thinkpad X201 Tablet to the video_detect_force_video blacklist.

Signed-off-by: Ralf Gerbig <rge@quengel.org>
[ rjw : Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>