tablet: always enable the proximity out quirk

Don't require a quirk update, just enable this by default for all tablets. If
we get a proximity out event at the right time, the quirk is disabled for that
tablet for the rest of its lifetime. And it's virtually impossible to have a
false positive here anyway - you cannot hold the pen still enough to not
trigger events for 50ms.

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