HID: wacom: Set a default resolution for older tablets

Some older tablets may not report physical maximum for X/Y
coordinates. Set a default to prevent undefined resolution.

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Link: https://lore.kernel.org/r/20230409164229.29777-1-ping.cheng@wacom.com
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>