Re-factor definition of TZC-400 base address

This patch replaces the `ARM_TZC_BASE` constant with `PLAT_ARM_TZC_BASE` to
support different TrustZone Controller base addresses across ARM platforms.

Change-Id: Ie4e1c7600fd7a5875323c7cc35e067de0c6ef6dd
diff --git a/include/plat/arm/css/common/css_def.h b/include/plat/arm/css/common/css_def.h
index 157a22f..e5005b9 100644
--- a/include/plat/arm/css/common/css_def.h
+++ b/include/plat/arm/css/common/css_def.h
@@ -111,6 +111,6 @@
 
 /* TZC related constants */
 #define PLAT_ARM_TZC_FILTERS		REG_ATTR_FILTER_BIT_ALL
-
+#define PLAT_ARM_TZC_BASE		0x2a4a0000
 
 #endif /* __CSS_DEF_H__ */