selftests/hid: tablets: remove unused class

Looks like this is a leftover

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Jiri Kosina <jkosina@suse.com>
Link: https://lore.kernel.org/r/20231206-wip-selftests-v2-4-c0350c2f5986@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

Author: Benjamin Tissoires

tools/testing/selftests/hid/tests/test_tablet.py

@@ -133,10 +133,6 @@ def valid_transitions(self) -> Tuple["PenState", ...]:
         return tuple()
 
 
-class Data(object):
-    pass
-
-
 class Pen(object):
     def __init__(self, x, y):
         self.x = x