tty: USB does not need the filp argument in the drivers

And indeed none of them use it. Clean this up as it will make moving to a
standard open method rather easier.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index e8bc42f..d4cc0f7 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -1831,8 +1831,7 @@
 	tty_kref_put(tty);
 }
 
-static int edge_open(struct tty_struct *tty,
-			struct usb_serial_port *port, struct file *filp)
+static int edge_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	struct edgeport_port *edge_port = usb_get_serial_port_data(port);
 	struct edgeport_serial *edge_serial;