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/common/include/nrd_dmc620_tzc_regions.h b/plat/arm/board/neoverse_rd/common/include/nrd_dmc620_tzc_regions.h
index a38c759..c63d750 100644
--- a/plat/arm/board/neoverse_rd/common/include/nrd_dmc620_tzc_regions.h
+++ b/plat/arm/board/neoverse_rd/common/include/nrd_dmc620_tzc_regions.h
@@ -10,7 +10,7 @@
 #include <drivers/arm/tzc_dmc620.h>
 
 #if SPM_MM
-#define CSS_SGI_DMC620_TZC_REGIONS_DEF				\
+#define NRD_DMC620_TZC_REGIONS_DEF				\
 	{							\
 		.region_base = ARM_AP_TZC_DRAM1_BASE,		\
 		.region_top = PLAT_SP_IMAGE_NS_BUF_BASE - 1,	\
@@ -25,7 +25,7 @@
 		.sec_attr = TZC_DMC620_REGION_S_RDWR		\
 	}
 #else
-#define CSS_SGI_DMC620_TZC_REGIONS_DEF				\
+#define NRD_DMC620_TZC_REGIONS_DEF				\
 	{							\
 		.region_base = ARM_AP_TZC_DRAM1_BASE,		\
 		.region_top = ARM_AP_TZC_DRAM1_END,		\