touchpad: end hovering touches in maybe_end_touch

Otherwise a hovering touch stays around forever even after the finger has
discontinued. This doesn't matter on slots, but for fake fingers the finger
may suddenly end up being forced down/up as a result of the pressure changes
on the real fingers.

So when in maybe_end_touch, switch them back to NONE immediately - hovering
touches do not need to trigger a TOUCH_END event.

https://bugs.freedesktop.org/show_bug.cgi?id=105258

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
(cherry picked from commit d8db6b5)

src/evdev-mt-touchpad.c

@@ -345,22 +345,26 @@ tp_maybe_end_touch(struct tp_dispatch *tp,
 	switch (t->state) {
 	case TOUCH_NONE:
 	case TOUCH_MAYBE_END:
-	case TOUCH_HOVERING:
 		return;
 	case TOUCH_END:
 		evdev_log_bug_libinput(tp->device,
 				       "touch  already in TOUCH_END\n");
 		return;
+	case TOUCH_HOVERING:
 	case TOUCH_BEGIN:
 	case TOUCH_UPDATE:
 		break;
 	}
 
-	t->dirty = true;
-	t->state = TOUCH_MAYBE_END;
+	if (t->state != TOUCH_HOVERING) {
+		assert(tp->nfingers_down >= 1);
+		tp->nfingers_down--;
+		t->state = TOUCH_MAYBE_END;
+	} else {
+		t->state = TOUCH_NONE;
+	}
 
-	assert(tp->nfingers_down >= 1);
-	tp->nfingers_down--;
+	t->dirty = true;
 }
 
 /**