mediatek: mt8183: add MTK SPM driver

Add MTK SPM driver for suspend/resume scenario.

Change-Id: I8207eea95914da9e63c62f3afc8329f3ccd9a22c
diff --git a/plat/mediatek/mt8183/drivers/spm/spm_suspend.h b/plat/mediatek/mt8183/drivers/spm/spm_suspend.h
new file mode 100644
index 0000000..e127c2e
--- /dev/null
+++ b/plat/mediatek/mt8183/drivers/spm/spm_suspend.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __SPM_SUSPEND_H__
+#define __SPM_SUSPEND_H__
+
+void spm_system_suspend(void);
+void spm_system_suspend_finish(void);
+
+#endif /* __SPM_SUSPEND_H__*/