USB: Serial: mct_u232.c: remove debug module parameter

Now that all usb-serial modules are only using dev_dbg()
the debug module parameter does not do anything at all, so
remove it to reduce any confusion if someone were to try to
use it.

CC: Johan Hovold <jhovold@gmail.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/mct_u232.c

@@ -45,8 +45,6 @@
 #define DRIVER_AUTHOR "Wolfgang Grandegger <wolfgang@ces.ch>"
 #define DRIVER_DESC "Magic Control Technology USB-RS232 converter driver"
 
-static bool debug;
-
 /*
  * Function prototypes
  */
@@ -878,6 +876,3 @@ module_usb_serial_driver(serial_drivers, id_table);
 MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
-
-module_param(debug, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(debug, "Debug enabled or not");