AArch32: resolve build error when LOG_LEVEL=50

This patch resolves a build error in Trusted Firmware when `ARCH=aarch32`
and LOG_LEVEL >= 50.

Change-Id: I62a23ded4a25304533cdcc5ff11442aee041709b
diff --git a/common/bl_common.c b/common/bl_common.c
index 6dcd4c1..bae02d4 100644
--- a/common/bl_common.c
+++ b/common/bl_common.c
@@ -419,9 +419,11 @@
 	PRINT_IMAGE_ARG(1);
 	PRINT_IMAGE_ARG(2);
 	PRINT_IMAGE_ARG(3);
+#ifndef AARCH32
 	PRINT_IMAGE_ARG(4);
 	PRINT_IMAGE_ARG(5);
 	PRINT_IMAGE_ARG(6);
 	PRINT_IMAGE_ARG(7);
+#endif
 #undef PRINT_IMAGE_ARG
 }