lib: utils: Add SiFive test device

This patch factor-out SiFive test device related stuff into
it's own source file from qemu/virt platform. In future, we
can find SiFive test device address from device tree as well.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

include/sbi_utils/sys/sifive_test.h

@@ -0,0 +1,19 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __SYS_SIFIVE_TEST_H__
+#define __SYS_SIFIVE_TEST_H__
+
+#include <sbi/sbi_types.h>
+
+int sifive_test_system_reset(u32 type);
+
+int sifive_test_init(unsigned long base);
+
+#endif