Revert "HID: multitouch: enable palm rejection if device implements confidence usage"

This reverts commit 25a84db1 ("HID: multitouch: enable palm rejection
if device implements confidence usage")

The commit enables palm rejection for Win8 Precision Touchpad devices but
the quirk MT_QUIRK_VALID_IS_CONFIDENCE it is using is not working very
properly. This quirk is originally designed for some WIn7 touchscreens. Use
of this for a Win8 Precision Touchpad will cause unexpected pointer jumping
problem.

Cc: stable@vger.kernel.org # v4.5+
Reviewed-by: NBenjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Andy Lutomirski <luto@kernel.org> # XPS 13 9350, BIOS 1.4.3
Signed-off-by: NAllen Hung <allen_hung@dell.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/hid-multitouch.c

@@ -502,11 +502,6 @@ static int mt_touch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 			mt_store_field(usage, td, hi);
 			return 1;
 		case HID_DG_CONFIDENCE:
-			if (cls->name == MT_CLS_WIN_8 &&
-				field->application == HID_DG_TOUCHPAD) {
-				cls->quirks &= ~MT_QUIRK_ALWAYS_VALID;
-				cls->quirks |= MT_QUIRK_VALID_IS_CONFIDENCE;
-			}
 			mt_store_field(usage, td, hi);
 			return 1;
 		case HID_DG_TIPSWITCH: