'wacom->data' contains raw binary data and can lead to unexpected behavior
if a byte under examination happens to have its MSB set.
Signed-off-by: NJason Gerecke <killertofu@gmail.com>
Tested-by: NAaron Skomra <Aaron.Skomra@wacom.com>
Reviewed-by: NCarl Worth <cworth@cworth.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>