rcar_gen3: plat: Add R-Car V3M support

Add R-Car V3M support. This is based on the original
V3M support patch for Yocto v2.23.1 by Vladimir Barinov.

Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Valentine Barshak <valentine.barshak@cogentembedded.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
---
Marek: Update on top of mainline ATF/master
diff --git a/drivers/renesas/rcar/board/board.h b/drivers/renesas/rcar/board/board.h
index 05c4e8a..51a8e30 100644
--- a/drivers/renesas/rcar/board/board.h
+++ b/drivers/renesas/rcar/board/board.h
@@ -16,7 +16,8 @@
 #define BOARD_STARTER_KIT_PRE		(0x0B)
 #define BOARD_EBISU_4D			(0x0DU)
 #define BOARD_DRAAK			(0x0EU)
-#define BOARD_UNKNOWN			(BOARD_DRAAK + 1U)
+#define BOARD_EAGLE			(0x0FU)
+#define BOARD_UNKNOWN			(BOARD_EAGLE + 1U)
 
 #define BOARD_REV_UNKNOWN		(0xFF)