HID: multitouch: new device class fix Lenovo X12 trackpad sticky
The trackpad of the given device sends continuous report of pointers
status as per wxn8 spec. However, the spec did not clarify when the
fingers are lifted so fast that between the interval of two report
frames fingers on pad reduced from >=2 to 0. The second last report
contains >=2 fingers with tip state 1 and the last report contains only
1 finger with tip state 0. Although this can happen unfrequently, a
quick fix will be improve the consistency to 100%. A quick fix is to
disable MT_QUIRK_ALWAYS_VALID and enable MT_QUIRK_NOT_SEEN_MEANS_UP.
Test for hid-tools is added in [1]
In addition to this, I2C device 04CA:00B1 may also need similar class
but with MT_QUIRK_FORCE_MULTI_INPUT disabled (but it does not harm to
enable it on non-multi-input device either). The respective owner has
been notified and a patch may coming soon after test.