software node: remove software_node_exit()

software_node_exit() is an __exitcall() in a built-in compilation unit
so effectively dead code. Remove it.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20260402-nokia770-gpio-swnodes-v5-2-d730db3dd299@oss.qualcomm.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Author: Bartosz Golaszewski

drivers/base/swnode.c

@@ -1135,10 +1135,3 @@ static int __init software_node_init(void)
 	return 0;
 }
 postcore_initcall(software_node_init);
-
-static void __exit software_node_exit(void)
-{
-	ida_destroy(&swnode_root_ids);
-	kset_unregister(swnode_kset);
-}
-__exitcall(software_node_exit);