Fix usage of IMAGE_BLx macros

These macros are only defined for corresponding image,
and they are undefined for other images. It means that we have
to use ifdef or defined() instead of relying on being 0 by default.

Change-Id: Iad11efab9830ddf471599b46286e1c56581ef5a7
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/plat/hisilicon/hikey/include/platform_def.h b/plat/hisilicon/hikey/include/platform_def.h
index 0180654..f4a3fd4 100644
--- a/plat/hisilicon/hikey/include/platform_def.h
+++ b/plat/hisilicon/hikey/include/platform_def.h
@@ -151,15 +151,15 @@
  */
 #define ADDR_SPACE_SIZE			(1ull << 32)
 
-#if IMAGE_BL1 || IMAGE_BL32
+#if defined(IMAGE_BL1) || defined(IMAGE_BL32)
 #define MAX_XLAT_TABLES			3
 #endif
 
-#if IMAGE_BL31
+#ifdef IMAGE_BL31
 #define MAX_XLAT_TABLES			4
 #endif
 
-#if IMAGE_BL2
+#ifdef IMAGE_BL2
 #if LOAD_IMAGE_V2
 #ifdef SPD_opteed
 #define MAX_XLAT_TABLES			4