mux: mux-core: unregister mux_class in mux_exit()

Fixes an obvious and nasty typo.

Fixes: a3b02a9c6591 ("mux: minimal mux subsystem")
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/mux/mux-core.c

@@ -46,7 +46,7 @@ static int __init mux_init(void)
 
 static void __exit mux_exit(void)
 {
-	class_register(&mux_class);
+	class_unregister(&mux_class);
 	ida_destroy(&mux_ida);
 }