Create a library file for libmbedtls

TF Makefile was linking all the objects files generated for the
Mbed TLS library instead of creating a static library that could be
used in the linking stage.

Change-Id: I8e4cd843ef56033c9d3faeee71601d110b7e4c12
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/bl1/bl1.mk b/bl1/bl1.mk
index 41ee1a7..9a46a34 100644
--- a/bl1/bl1.mk
+++ b/bl1/bl1.mk
@@ -14,9 +14,7 @@
 				lib/el3_runtime/${ARCH}/context_mgmt.c	\
 				plat/common/plat_bl1_common.c		\
 				plat/common/${ARCH}/platform_up_stack.S \
-				${MBEDTLS_COMMON_SOURCES}		\
-				${MBEDTLS_CRYPTO_SOURCES}		\
-				${MBEDTLS_X509_SOURCES}
+				${MBEDTLS_SOURCES}
 
 ifeq (${ARCH},aarch64)
 BL1_SOURCES		+=	lib/el3_runtime/aarch64/context.S