plat/arm/sgi: add system-id node in HW_CONFIG dts

Dynamically populating the 'system-id' node in the HW_CONFIG dts makes
it difficult to enforce memory overlap checks. So add the system-id node
in the HW_CONFIG dts file as a place holder with 'platform-id' and
'config-id' set to zero.

The code at BL2 stage determines the values of 'platform-id' and
'config-id' at runtime and updates the corresponding fields in the
system-id node of HW_CONFIG dts.

Change-Id: I2ca9980b994ac418da8afa0c72716ede10aff68a
Signed-off-by: Chandni Cherukuri <chandni.cherukuri@arm.com>
diff --git a/plat/arm/board/sgi575/fdts/sgi575.dts b/plat/arm/board/sgi575/fdts/sgi575.dts
index be9920c..1e1ea14 100644
--- a/plat/arm/board/sgi575/fdts/sgi575.dts
+++ b/plat/arm/board/sgi575/fdts/sgi575.dts
@@ -8,4 +8,14 @@
 / {
 	/* compatible string */
 	compatible = "arm,sgi575";
+
+	/*
+	 * Place holder for system-id node with default values. The
+	 * value of platform-id and config-id will be set to the
+	 * correct values during the BL2 stage of boot.
+	 */
+	system-id {
+		platform-id = <0x0>;
+		config-id = <0x0>;
+	};
 };