HID: multitouch: fix touchpad buttons

Commit "HID: multitouch: use the callback "report" instead..." breaks the
buttons of touchpads following the HID multitouch specification.
The buttons were emmitted through hid-input, but as now the events
are generated only in hid-multitouch, the buttons are not emmitted anymore.

The input_event() call is far much simpler than the hid-input one as
many of the different tests do not apply to multitouch touchpads.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-multitouch.c

@@ -621,6 +621,7 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
 {
 	struct mt_device *td = hid_get_drvdata(hid);
 	__s32 quirks = td->mtclass.quirks;
+	struct input_dev *input = field->hidinput->input;
 
 	if (hid->claimed & HID_CLAIMED_INPUT) {
 		switch (usage->hid) {
@@ -670,13 +671,16 @@ static void mt_process_mt_event(struct hid_device *hid, struct hid_field *field,
 			break;
 
 		default:
+			if (usage->type)
+				input_event(input, usage->type, usage->code,
+						value);
 			return;
 		}
 
 		if (usage->usage_index + 1 == field->report_count) {
 			/* we only take into account the last report. */
 			if (usage->hid == td->last_slot_field)
-				mt_complete_slot(td, field->hidinput->input);
+				mt_complete_slot(td, input);
 
 			if (field->index == td->last_field_index
 				&& td->num_received >= td->num_expected)