USB: serial: cp210x.c: remove debug module parameter

Now that the dbg() macro is no longer being used in the driver,
the debug module parameter doesn't do anything at all.  So remove
it so as to not confuse people.

CC: Johan Hovold <jhovold@gmail.com>
CC: Preston Fick <preston.fick@silabs.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/cp210x.c

@@ -52,8 +52,6 @@ static int cp210x_startup(struct usb_serial *);
 static void cp210x_release(struct usb_serial *);
 static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
 
-static bool debug;
-
 static const struct usb_device_id id_table[] = {
 	{ USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
 	{ USB_DEVICE(0x0471, 0x066A) }, /* AKTAKOM ACE-1001 cable */
@@ -884,6 +882,3 @@ module_usb_serial_driver(serial_drivers, id_table);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL");
-
-module_param(debug, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(debug, "Enable verbose debugging messages");