fix big endian toolchain build

target/config/Config.in.cpu

@@ -124,7 +124,8 @@ config ADK_TARGET_CPU_ARCH
 	default "armv6" if ADK_LINUX_ARM && ADK_little && ADK_armv6
 	default "armv7a" if ADK_LINUX_ARM && ADK_little && ADK_armv7a
 	default "arm" if ADK_LINUX_ARM && ADK_little
-	default "arc" if ADK_CPU_ARC
+	default "arc" if ADK_CPU_ARC && ADK_little
+	default "arceb" if ADK_CPU_ARC && ADK_big
 	default "bfin" if ADK_CPU_BFIN
 	default "i486" if ADK_CPU_I486
 	default "i586" if ADK_CPU_I586