Fix naming: FFDH key -> DH key and fix guard in psa_validate_key_type_and_size_for_key_generation

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/library/psa_crypto_ffdh.h b/library/psa_crypto_ffdh.h
index 950646a..62b05b2 100644
--- a/library/psa_crypto_ffdh.h
+++ b/library/psa_crypto_ffdh.h
@@ -60,7 +60,7 @@
     size_t shared_secret_size,
     size_t *shared_secret_length);
 
-/** Export a public key or the public part of a FFDH key pair in binary format.
+/** Export a public key or the public part of a DH key pair in binary format.
  *
  * \param[in]  attributes       The attributes for the key to export.
  * \param[in]  key_buffer       Material or context of the key to export.
@@ -86,7 +86,7 @@
     size_t *data_length);
 
 /**
- * \brief Generate FFDH key.
+ * \brief Generate DH key.
  *
  * \note The signature of the function is that of a PSA driver generate_key
  *       entry point.