ta/crypt: add arithmetic TAF wrappers

Adds TAF wrappers for GP TEE arithmetical API

Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/ta/crypt/sub.mk b/ta/crypt/sub.mk
index e9fb0a6..dcdde55 100644
--- a/ta/crypt/sub.mk
+++ b/ta/crypt/sub.mk
@@ -7,6 +7,8 @@
 srcs-$(CFG_SYSTEM_PTA) += seed_rng_taf.c
 srcs-y += ta_entry.c
 srcs-$(CFG_TA_MBEDTLS) += mbedtls_taf.c
+srcs-y += arith_taf.c
+srcs-y += handle.c
 
 CRYPT_FILE_TO_C_SCRIPT = ../../scripts/file_to_c.py
 CRYPT_CA_CRT = ../../certs/ca.crt