Input: Use accessor for MT values

The current MT accessor function does not distinguish between the MT
values and the slot specification event. Add an accessor function for
the values only, and use it where appropriate.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>

drivers/input/input.c

@@ -180,7 +180,7 @@ static int input_handle_abs_event(struct input_dev *dev,
 		return INPUT_IGNORE_EVENT;
 	}
 
-	is_mt_event = code >= ABS_MT_FIRST && code <= ABS_MT_LAST;
+	is_mt_event = input_is_mt_value(code);
 
 	if (!is_mt_event) {
 		pold = &dev->absinfo[code].value;