refactor(measured-boot): add generic macros for using Crypto library

It doesn't look correct to use mbed TLS defines directly in the Event
Log driver as this driver may use another Crypto library in future.
Hence mbed TLS Crypto dependency on Event Log driver is removed by
introducing generic Crypto defines and uses those in the Event Log
driver to call Crypto functions.
Also, updated mbed TLS glue layer to map these generic Crypto defines
to mbed TLS library defines.

Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: Ibc9c751f60cbce4d3f3cf049b7c53b3d05cc6735
diff --git a/drivers/measured_boot/event_log/event_log.mk b/drivers/measured_boot/event_log/event_log.mk
index 37e5e29..d3fbbb5 100644
--- a/drivers/measured_boot/event_log/event_log.mk
+++ b/drivers/measured_boot/event_log/event_log.mk
@@ -12,35 +12,24 @@
 TPM_HASH_ALG			:=	sha256
 
 ifeq (${TPM_HASH_ALG}, sha512)
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA512
     TPM_ALG_ID			:=	TPM_ALG_SHA512
     TCG_DIGEST_SIZE		:=	64U
 else ifeq (${TPM_HASH_ALG}, sha384)
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA384
     TPM_ALG_ID			:=	TPM_ALG_SHA384
     TCG_DIGEST_SIZE		:=	48U
 else
-    MBEDTLS_MD_ID		:=	MBEDTLS_MD_SHA256
     TPM_ALG_ID			:=	TPM_ALG_SHA256
     TCG_DIGEST_SIZE		:=	32U
-endif
+endif #TPM_HASH_ALG
 
-
-# Set definitions for mbed TLS library and Measured Boot driver
+# Set definitions for Measured Boot driver.
 $(eval $(call add_defines,\
     $(sort \
-        MBEDTLS_MD_ID \
         TPM_ALG_ID \
         TCG_DIGEST_SIZE \
         EVENT_LOG_LEVEL \
 )))
 
-ifeq (${HASH_ALG}, sha256)
-    ifneq (${TPM_HASH_ALG}, sha256)
-        $(eval $(call add_define,MBEDTLS_SHA512_C))
-    endif
-endif
-
 MEASURED_BOOT_SRC_DIR	:= drivers/measured_boot/event_log/
 
 MEASURED_BOOT_SOURCES	:= ${MEASURED_BOOT_SRC_DIR}event_log.c		\