hwmon: (adm1029) Add SPDX header

This patch addes SPDX header to adm1029

Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/adm1029.c b/drivers/hwmon/adm1029.c
index 3dd4c84..381bfae 100644
--- a/drivers/hwmon/adm1029.c
+++ b/drivers/hwmon/adm1029.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * adm1029.c - Part of lm_sensors, Linux kernel modules for hardware monitoring
  *