platform: Add Andes AE350 initial support

This commit provides basic support for the AE350 platform.

Signed-off-by: Zong Li <zongbox@gmail.com>
Signed-off-by: Nylon Chen <nylon7@andestech.com>

platform/andes/ae350/plmt.h

@@ -0,0 +1,23 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Andes Technology Corporation
+ *
+ * Authors:
+ *   Zong Li <zong@andestech.com>
+ */
+
+#ifndef _AE350_PLMT_H_
+#define _AE350_PLMT_H_
+
+u64 plmt_timer_value(void);
+
+void plmt_timer_event_stop(void);
+
+void plmt_timer_event_start(u64 next_event);
+
+int plmt_warm_timer_init(void);
+
+int plmt_cold_timer_init(unsigned long base, u32 hart_count);
+
+#endif /* _AE350_PLMT_H_ */