Draft: hack: Input: edt-ft5x06: let any EVENT_UP release all slots
When touching 2 or more fingers simultaniously, the EVENT_DOWN data seems to be received accurately. But when releasing all of them, EVENT_UP sometimes is received only once. This results in a broken state where slots stay "active" and a subsequent "tap" is not recognized by userspace (because userspace sees an ongoing long touch point from before, and the "tap" is a 2nd or 3rd touch point).
Work around this in a pretty hacky way that breaks transitioning from (n) touch points to (n-1), where n>1. Always "release" all "active" touch points on any single EVENT_UP received.
Inspired by: OS-issues#288