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/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index 8839f1c..20432d3 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -933,8 +933,7 @@
 
 
 
-static int garmin_open(struct tty_struct *tty,
-			struct usb_serial_port *port, struct file *filp)
+static int garmin_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
 	unsigned long flags;
 	int status = 0;