Fix Keymapping for upcoming Dell Laptops

Fix Keymapping for upcoming Dell Laptops

This patch fixes it so that new upcoming Dell machines will work
correctly if users presses the touchpad toggle key.

Currently 0xD8 is being mapped to sleep. Though this is only done by the
Latitude XT* laptops. Many upcoming Laptops from Dell are mapping this
key to "toogle touchpad off" .. giving the OS notification that it has
just turned off the touchpad.

Though their is an issue in that if this key is mapped the hardware
first toogles .. then the software tries to do the samething after, if
they fall out of sync ... no more touchpad. So leave out mapping these
keys for now.

Signed-off-by: Jerone Young <jerone.young@canonical.com>
Signed-off-by: Martin Pitt <martin.pitt@ubuntu.com>