USB: Serial: usb-serial: 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.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
index 335f98d..6ea18a1 100644
--- a/drivers/usb/serial/console.c
+++ b/drivers/usb/serial/console.c
@@ -22,8 +22,6 @@
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 
-static int debug;
-
 struct usbcons_info {
 	int			magic;
 	int			break_flag;
@@ -283,10 +281,8 @@
 	}
 }
 
-void usb_serial_console_init(int serial_debug, int minor)
+void usb_serial_console_init(int minor)
 {
-	debug = serial_debug;
-
 	if (minor == 0) {
 		/*
 		 * Call register_console() if this is the first device plugged