feat(board/rdn2): add support for variant 1 of rd-n2 platform

Add board support for RD-N2 Cfg1 variant of RD-N2 platform. It is a
variant of RD-N2 platform with a reduced interconnect mesh size (3x3)
and core count (8-cores). Its platform variant id is 1.

Change-Id: I34ad35c5a5c1e9b69a658fb92ed00e5bc5fe72f3
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>
diff --git a/plat/arm/css/sgi/include/sgi_variant.h b/plat/arm/css/sgi/include/sgi_variant.h
index ecf6d93..0062b97 100644
--- a/plat/arm/css/sgi/include/sgi_variant.h
+++ b/plat/arm/css/sgi/include/sgi_variant.h
@@ -20,6 +20,9 @@
 /* SID Version values for RD-N2 */
 #define RD_N2_SID_VER_PART_NUM			0x07B7
 
+/* SID Version values for RD-N2 variants */
+#define RD_N2_CFG1_SID_VER_PART_NUM		0x07B6
+
 /* Structure containing SGI platform variant information */
 typedef struct sgi_platform_info {
 	unsigned int platform_id;	/* Part Number of the platform */