refactor(neoverse-rd): header files for first generation platforms

Presently, platforms such as SGI-575, RD-N1-Edge single and dual chip,
RD_V1 single and multi-chip utilize nrd_soc_platform_def.h and
nrd_soc_css_def.h for all css and soc-related defines. So move these
two header files into a new directory named 'nrd1'. This new directory
will serve as the container of header files that are specific to
SGI-575, RD-N1 and RD-V1 platform and its variants.

Signed-off-by: Rohit Mathew <rohit.mathew@arm.com>
Change-Id: I9d70659c6f5000ad6c1cfc0738f9e81f03238f5f

plat/arm/board/neoverse_rd/platform/rdn1edge/platform.mk

@@ -13,7 +13,8 @@ include plat/arm/board/neoverse_rd/common/nrd-common.mk
 
 RDN1EDGE_BASE		=	plat/arm/board/neoverse_rd/platform/rdn1edge
 
-PLAT_INCLUDES		+=	-I${RDN1EDGE_BASE}/include/
+PLAT_INCLUDES		+=	-I${NRD_COMMON_BASE}/include/nrd1/	\
+				-I${RDN1EDGE_BASE}/include/
 
 NRD_CPU_SOURCES		:=	lib/cpus/aarch64/neoverse_n1.S
 

plat/arm/board/neoverse_rd/platform/rdv1/platform.mk

@@ -10,7 +10,8 @@ include plat/arm/board/neoverse_rd/common/nrd-common.mk
 
 RDV1_BASE		=	plat/arm/board/neoverse_rd/platform/rdv1
 
-PLAT_INCLUDES		+=	-I${RDV1_BASE}/include/
+PLAT_INCLUDES		+=	-I${NRD_COMMON_BASE}/include/nrd1/	\
+				-I${RDV1_BASE}/include/
 
 NRD_CPU_SOURCES		:=	lib/cpus/aarch64/neoverse_v1.S
 

plat/arm/board/neoverse_rd/platform/rdv1mc/platform.mk

@@ -11,7 +11,8 @@ include plat/arm/board/neoverse_rd/common/nrd-common.mk
 
 RDV1MC_BASE	=	plat/arm/board/neoverse_rd/platform/rdv1mc
 
-PLAT_INCLUDES		+=	-I${RDV1MC_BASE}/include/
+PLAT_INCLUDES		+=	-I${NRD_COMMON_BASE}/include/nrd1/	\
+				-I${RDV1MC_BASE}/include/
 
 NRD_CPU_SOURCES		:=	lib/cpus/aarch64/neoverse_v1.S
 

plat/arm/board/neoverse_rd/platform/sgi575/platform.mk

@@ -10,7 +10,8 @@ include plat/arm/board/neoverse_rd/common/nrd-common.mk
 
 SGI575_BASE		=	plat/arm/board/neoverse_rd/platform/sgi575
 
-PLAT_INCLUDES		+=	-I${SGI575_BASE}/include/
+PLAT_INCLUDES		+=	-I${NRD_COMMON_BASE}/include/nrd1/	\
+				-I${SGI575_BASE}/include/
 
 NRD_CPU_SOURCES		:=	lib/cpus/aarch64/cortex_a75.S