vt: delete unneeded function unregister_con_driver

Now there is no place use unregister_con_driver,
and we can achieve unregister_con_driver's function
with unregister_con_driver easily, so just delete it
to reduce code size and duplication.
Signed-off-by: NWang YanQing <udknight@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt.c

@@ -3545,7 +3545,7 @@ static int do_register_con_driver(const struct consw *csw, int first, int last)
 
 
 /**
- * unregister_con_driver - unregister console driver from console layer
+ * do_unregister_con_driver - unregister console driver from console layer
  * @csw: console driver
  *
  * DESCRIPTION: All drivers that registers to the console layer must
@@ -3555,17 +3555,6 @@ static int do_register_con_driver(const struct consw *csw, int first, int last)
  *
  * The driver must unbind first prior to unregistration.
  */
-int unregister_con_driver(const struct consw *csw)
-{
-	int retval;
-
-	console_lock();
-	retval = do_unregister_con_driver(csw);
-	console_unlock();
-	return retval;
-}
-EXPORT_SYMBOL(unregister_con_driver);
-
 int do_unregister_con_driver(const struct consw *csw)
 {
 	int i, retval = -ENODEV;

include/linux/console.h

@@ -75,7 +75,6 @@ extern const struct consw newport_con;	/* SGI Newport console  */
 extern const struct consw prom_con;	/* SPARC PROM console */
 
 int con_is_bound(const struct consw *csw);
-int unregister_con_driver(const struct consw *csw);
 int do_unregister_con_driver(const struct consw *csw);
 int do_take_over_console(const struct consw *sw, int first, int last, int deflt);
 void give_up_console(const struct consw *sw);