Fix ARM32 and AARCH64 builds

Without these added into SUBDIRS the initplat.c compilation will fail.

Signed-off-by: Koen Kooi <koen.kooi@linaro.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Nigel Croxon <nigel.croxon@hp.com>

lib/Makefile

@@ -63,7 +63,7 @@ endif
 
 OBJS  = $(FILES:%=%.o)
 
-SUBDIRS = ia32 x86_64 ia64 runtime
+SUBDIRS = ia32 x86_64 ia64 aarch64 arm runtime
 
 LIBDIRINSTALL = $(INSTALLROOT)$(LIBDIR)