libc: Add AArch32 and AArch64 headers

Change-Id: I4f58bb4660078c9bc76d2826c90b2fa711719a3e
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/lib/libc/libc.mk b/lib/libc/libc.mk
index 575a2aa..0dee4f5 100644
--- a/lib/libc/libc.mk
+++ b/lib/libc/libc.mk
@@ -24,4 +24,4 @@
 			subr_prf.c)
 
 INCLUDES	+=	-Iinclude/lib/libc		\
-			-Iinclude/lib/libc/sys
+			-Iinclude/lib/libc/$(ARCH)	\