renesas: rzg: Add support to identify EK874 RZ/G2E board

Add support to identify Silicon Linux RZ/G2E evaluation kit (EK874).

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Change-Id: Id7bdbc9b0d25aa9af496d58d4bd5055579edc104
diff --git a/drivers/renesas/rzg/board/board.h b/drivers/renesas/rzg/board/board.h
index 7165d45..1a76849 100644
--- a/drivers/renesas/rzg/board/board.h
+++ b/drivers/renesas/rzg/board/board.h
@@ -11,6 +11,7 @@
 	BOARD_HIHOPE_RZ_G2M = 0,
 	BOARD_HIHOPE_RZ_G2H,
 	BOARD_HIHOPE_RZ_G2N,
+	BOARD_EK874_RZ_G2E,
 	BOARD_UNKNOWN
 };