The current tests worked because all rings had the same range, so our error
margin covered for that. With the upcoming MobileStudio Pro 16 pad device, the
range is half and our error margins don't work anymore. Switch to a more
reliable approach that tests every integer value the wheel can send, even
though it relies on kernel filtering.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>