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/pl2303.c b/drivers/usb/serial/pl2303.c
index 3e86815..a63ea99 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -691,8 +691,7 @@
 
 }
 
-static int pl2303_open(struct tty_struct *tty,
-			struct usb_serial_port *port, struct file *filp)
+static int pl2303_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	struct ktermios tmp_termios;
 	struct usb_serial *serial = port->serial;
@@ -714,8 +713,6 @@
 	if (tty)
 		pl2303_set_termios(tty, port, &tmp_termios);
 
-	/* FIXME: need to assert RTS and DTR if CRTSCTS off */
-
 	dbg("%s - submitting read urb", __func__);
 	port->read_urb->dev = serial->dev;
 	result = usb_submit_urb(port->read_urb, GFP_KERNEL);