Input: i8042 - print debug data when testing AUX IRQ delivery

Sometimes it is not clear why IRQ delivery test failed so let's
add some debug printks so we know the exact reason.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/serio/i8042.c

@@ -609,6 +609,8 @@ static irqreturn_t __init i8042_aux_test_irq(int irq, void *dev_id)
 	str = i8042_read_status();
 	if (str & I8042_STR_OBF) {
 		data = i8042_read_data();
+		dbg("%02x <- i8042 (aux_test_irq, %s)",
+			data, str & I8042_STR_AUXDATA ? "aux" : "kbd");
 		if (i8042_irq_being_tested &&
 		    data == 0xa5 && (str & I8042_STR_AUXDATA))
 			complete(&i8042_aux_irq_delivered);
@@ -750,6 +752,7 @@ static int __init i8042_check_aux(void)
  * AUX IRQ was never delivered so we need to flush the controller to
  * get rid of the byte we put there; otherwise keyboard may not work.
  */
+		dbg("     -- i8042 (aux irq test timeout)");
 		i8042_flush();
 		retval = -1;
 	}