mbedtls: add MSCode parser porting layer

Add porting layer for MSCode on top of MbedTLS ASN1 library.
Introduce _MBEDTLS kconfigs for MSCode MbedTLS implementation.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/mbedtls/Makefile b/lib/mbedtls/Makefile
index 128a29c..488b664 100644
--- a/lib/mbedtls/Makefile
+++ b/lib/mbedtls/Makefile
@@ -17,6 +17,7 @@
 obj-$(CONFIG_$(SPL_)X509_CERTIFICATE_PARSER_MBEDTLS) += \
 	x509_cert_parser.o
 obj-$(CONFIG_$(SPL_)PKCS7_MESSAGE_PARSER_MBEDTLS) += pkcs7_parser.o
+obj-$(CONFIG_$(SPL_)MSCODE_PARSER_MBEDTLS) += mscode_parser.o
 
 # MbedTLS crypto library
 obj-$(CONFIG_MBEDTLS_LIB) += mbedtls_lib_crypto.o