Input: goodix - fix spurious key release events

The goodix panel sends spurious interrupts after a 'finger up' event,
which always cause a timeout.
We were exiting the interrupt handler by reporting touch_num == 0, but
this was still processed as valid and caused the code to use the
uninitialised point_data, creating spurious key release events.

Report an error from the interrupt handler so as to avoid processing
invalid point_data further.
Signed-off-by: Dmitry Mastykin <dmastykin@astralinux.ru>
Reviewed-by: Bastien Nocera <hadess@hadess.net>
Link: https://lore.kernel.org/r/20200316075302.3759-2-dmastykin@astralinux.ruSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/touchscreen/goodix.c

@@ -345,7 +345,7 @@ static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
 	 * The Goodix panel will send spurious interrupts after a
 	 * 'finger up' event, which will always cause a timeout.
 	 */
-	return 0;
+	return -ENOMSG;
 }
 
 static void goodix_ts_report_touch_8b(struct goodix_ts_data *ts, u8 *coor_data)