lib: utils: Add simple FDT based system suspend driver framework

The generic platform can have multiple system suspend drivers so add a
simple FDT based system suspend driver framework.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>

include/sbi_utils/suspend/fdt_suspend.h

@@ -0,0 +1,26 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Ventana Micro Systems Inc.
+ *
+ * Authors:
+ *   Anup Patel <apatel@ventanamicro.com>
+ */
+
+#ifndef __FDT_SUSPEND_H__
+#define __FDT_SUSPEND_H__
+
+#include <sbi/sbi_types.h>
+#include <sbi_utils/fdt/fdt_driver.h>
+
+#ifdef CONFIG_FDT_SUSPEND
+
+void fdt_suspend_init(const void *fdt);
+
+#else
+
+static inline void fdt_suspend_init(const void *fdt) { }
+
+#endif
+
+#endif