fujitsu-tablet: add support for Lifebook T901 and T902

The button mappings for the Fujitsu Lifebook T901 and T902 are quite different
from the generic Lifebook T mappings that are defined. This patch adds
mappings that are specific to the hardware on these machines, and allows
users to take advantage of features like screen rotation.

Signed-off-by: Scott K Logan <logans@cottsay.net>
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>