Add psa_crypto_ffdh to build

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt
index 5359883..288024b 100644
--- a/library/CMakeLists.txt
+++ b/library/CMakeLists.txt
@@ -69,6 +69,7 @@
     psa_crypto_client.c
     psa_crypto_driver_wrappers.c
     psa_crypto_ecp.c
+    psa_crypto_ffdh.c
     psa_crypto_hash.c
     psa_crypto_mac.c
     psa_crypto_pake.c