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>
diff --git a/drivers/mux/mux-core.c b/drivers/mux/mux-core.c
index 90b8995..2fe96c4 100644
--- a/drivers/mux/mux-core.c
+++ b/drivers/mux/mux-core.c
@@ -46,7 +46,7 @@
 
 static void __exit mux_exit(void)
 {
-	class_register(&mux_class);
+	class_unregister(&mux_class);
 	ida_destroy(&mux_ida);
 }