Fix MISRA rule 8.4 in common code

Rule 8.4: A compatible declaration shall be visible when
          an object or function with external linkage is defined.

Change-Id: I26e042cb251a6f9590afa1340fdac73e42f23979
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/Makefile b/Makefile
index 87e35e9..db15930 100644
--- a/Makefile
+++ b/Makefile
@@ -200,6 +200,8 @@
 				${STDLIB_SRCS}
 
 INCLUDES		+=	-Iinclude/bl1				\
+				-Iinclude/bl2				\
+				-Iinclude/bl2u				\
 				-Iinclude/bl31				\
 				-Iinclude/common			\
 				-Iinclude/common/${ARCH}		\