Input: Break out MT data

Move all MT-related things to a separate place. This saves some
bytes for non-mt input devices, and prepares for new MT features.

Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Tested-by: Ping Cheng <pingc@wacom.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 8921c61..79a4a2a 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -166,6 +166,7 @@
 static int input_handle_abs_event(struct input_dev *dev,
 				  unsigned int code, int *pval)
 {
+	struct input_mt *mt = dev->mt;
 	bool is_mt_event;
 	int *pold;
 
@@ -174,8 +175,8 @@
 		 * "Stage" the event; we'll flush it later, when we
 		 * get actual touch data.
 		 */
-		if (*pval >= 0 && *pval < dev->mtsize)
-			dev->slot = *pval;
+		if (mt && *pval >= 0 && *pval < mt->num_slots)
+			mt->slot = *pval;
 
 		return INPUT_IGNORE_EVENT;
 	}
@@ -184,9 +185,8 @@
 
 	if (!is_mt_event) {
 		pold = &dev->absinfo[code].value;
-	} else if (dev->mt) {
-		struct input_mt_slot *mtslot = &dev->mt[dev->slot];
-		pold = &mtslot->abs[code - ABS_MT_FIRST];
+	} else if (mt) {
+		pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
 	} else {
 		/*
 		 * Bypass filtering for multi-touch events when
@@ -205,9 +205,9 @@
 	}
 
 	/* Flush pending "slot" event */
-	if (is_mt_event && dev->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
-		input_abs_set_val(dev, ABS_MT_SLOT, dev->slot);
-		input_pass_event(dev, EV_ABS, ABS_MT_SLOT, dev->slot);
+	if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
+		input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
+		input_pass_event(dev, EV_ABS, ABS_MT_SLOT, mt->slot);
 	}
 
 	return INPUT_PASS_TO_HANDLERS;
@@ -1751,8 +1751,8 @@
 	int i;
 	unsigned int events;
 
-	if (dev->mtsize) {
-		mt_slots = dev->mtsize;
+	if (dev->mt) {
+		mt_slots = dev->mt->num_slots;
 	} else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
 		mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
 			   dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,