arch: arm: npcm8xx: add cpu version and 4G ram support

Add npcm8xx A2 cpu version check
and add 4G RAM support

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
diff --git a/arch/arm/include/asm/arch-npcm8xx/gcr.h b/arch/arm/include/asm/arch-npcm8xx/gcr.h
index ee6677a..20230d6 100644
--- a/arch/arm/include/asm/arch-npcm8xx/gcr.h
+++ b/arch/arm/include/asm/arch-npcm8xx/gcr.h
@@ -12,6 +12,7 @@
 /* On-Chip ARBEL NPCM8XX VERSIONS */
 #define ARBEL_Z1			0x00A35850
 #define ARBEL_A1			0x04a35850
+#define ARBEL_A2			0x08a35850
 #define ARBEL_NPCM845			0x00000000
 #define ARBEL_NPCM830			0x00300395
 #define ARBEL_NPCM810			0x00000220