audit: replace atomic_add_return()

atomic_inc_return() is a little neater
Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

kernel/audit.c

@@ -1779,7 +1779,7 @@ unsigned int audit_serial(void)
 {
 	static atomic_t serial = ATOMIC_INIT(0);
 
-	return atomic_add_return(1, &serial);
+	return atomic_inc_return(&serial);
 }
 
 static inline void audit_get_stamp(struct audit_context *ctx,