Add psa_crypto_ffdh to build

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/library/Makefile b/library/Makefile
index 160aa6b..5c4471e 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -134,6 +134,7 @@
 	     psa_crypto_client.o \
 	     psa_crypto_driver_wrappers.o \
 	     psa_crypto_ecp.o \
+		 psa_crypto_ffdh.o \
 	     psa_crypto_hash.o \
 	     psa_crypto_mac.o \
 	     psa_crypto_pake.o \