pstore: Avoid race in module unloading

Technically, it might be possible for struct pstore_info to go out of
scope after the module_put(), so report the backend name first.
Signed-off-by: Kees Cook <keescook@chromium.org>

fs/pstore/platform.c

@@ -722,10 +722,10 @@ int pstore_register(struct pstore_info *psi)
 	 */
 	backend = psi->name;
 
-	module_put(owner);
-
 	pr_info("Registered %s as persistent store backend\n", psi->name);
 
+	module_put(owner);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_register);