Input: wacom - fix 3rd-gen Bamboo MT when 4+ fingers are in use

The message count field uses three bits of storage, not two.
Signed-off-by: Jason Gerecke <killertofu@gmail.com>
Acked-by: Chris Bagwell <chris@cnpbagwell.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/tablet/wacom_wac.c

@@ -926,7 +926,7 @@ static int wacom_bpt3_touch(struct wacom_wac *wacom)
 {
 	struct input_dev *input = wacom->input;
 	unsigned char *data = wacom->data;
-	int count = data[1] & 0x03;
+	int count = data[1] & 0x07;
 	int i;
 
 	if (data[0] != 0x02)