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/mos7720.c b/drivers/usb/serial/mos7720.c
index 4342a8a..763e32a 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -319,8 +319,7 @@
 	return status;
 }
 
-static int mos7720_open(struct tty_struct *tty,
-			struct usb_serial_port *port, struct file *filp)
+static int mos7720_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	struct usb_serial *serial;
 	struct usb_serial_port *port0;