arm: meson: implement calls to secure monitor

Implement calls to secure monitor to read the MAC address from e-fuse.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>

arch/arm/include/asm/arch-meson/sm.h

@@ -0,0 +1,12 @@
+/*
+ * (C) Copyright 2016 - Beniamino Galvani <b.galvani@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __MESON_SM_H__
+#define __MESON_SM_H__
+
+ssize_t meson_sm_read_efuse(uintptr_t offset, void *buffer, size_t size);
+
+#endif /* __MESON_SM_H__ */