usb/serial: fix function args warnings, dropping *filp

Fix build warnings caused by removal of *filp arg in struct
usb_serial_driver.

These changes were missed somehow in commits 00a0d0d65b61 ("tty: remove
filp from the USB tty ioctls") and 60b33c133ca0b ("tiocmget: kill off
the passing of the struct file")

  drivers/usb/serial/mct_u232.c:159: warning: initialization from incompatible pointer type
  drivers/usb/serial/opticon.c:627: warning: initialization from incompatible pointer type

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 201f609..a1dd4d4 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -413,7 +413,7 @@
 	return result;
 }
 
-static int opticon_tiocmset(struct tty_struct *tty, struct file *file,
+static int opticon_tiocmset(struct tty_struct *tty,
 			   unsigned int set, unsigned int clear)
 {
 	struct usb_serial_port *port = tty->driver_data;