The recommended way to have libinput ignore specific devices so far was to
remove the ID_INPUT* properties from the device. That may also affect other
pieces of the stack that need access to this device.

For the niche case of a device that should only be ignored by libinput but
otherwise be treated normally by the system, we now support the
LIBINPUT_IGNORE_DEVICE property.

If the property is set to "0", it's equivalent to being unset. This gets
around some technical limitations in udev where unsetting a property is
impossible via a hwdb entry.

https://bugs.freedesktop.org/show_bug.cgi?id=102229



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