efivars: Use to_efivar_entry

Use to_efivar_entry() instead of open-coding it.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Link: http://lkml.kernel.org/r/1454364428-494-9-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 756eca8..c5b0d2b 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -386,7 +386,7 @@
 
 static void efivar_release(struct kobject *kobj)
 {
-	struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
+	struct efivar_entry *var = to_efivar_entry(kobj);
 	kfree(var);
 }