refactor(sgi): rename "CSS_SGI"" macro prefixes to "NRD"

As of now, several internal macros utilize "CSS_SGI" as their prefix.
Given the change to neoverse_rd, and the subsequent migration out of the
css directory, the prefix "CSS_SGI" is no longer appropriate.
Therefore, update the macro prefixes to "NRD" for consistency and
clarity.

Signed-off-by: Rohit Mathew <Rohit.Mathew@arm.com>
Change-Id: I3d1a9dba3e83f6e107379fc5bcf8256cc93d8c3d
diff --git a/plat/arm/board/neoverse_rd/platform/rdv1mc/rdv1mc_security.c b/plat/arm/board/neoverse_rd/platform/rdv1mc/rdv1mc_security.c
index 8f371c5..d437def 100644
--- a/plat/arm/board/neoverse_rd/platform/rdv1mc/rdv1mc_security.c
+++ b/plat/arm/board/neoverse_rd/platform/rdv1mc/rdv1mc_security.c
@@ -56,7 +56,7 @@
 		INFO("Configuring TrustZone Controller for Chip %u\n", i);
 
 		for (j = 0; j < TZC400_COUNT; j++) {
-			arm_tzc400_setup(CSS_SGI_REMOTE_CHIP_MEM_OFFSET(i)
+			arm_tzc400_setup(NRD_REMOTE_CHIP_MEM_OFFSET(i)
 				+ TZC400_BASE(j), tzc_regions_mc[i-1]);
 		}
 	}