Return 'Feature unavailable' error for ciphers unsupported by PSA
diff --git a/library/cipher.c b/library/cipher.c
index 95146ac..1cc0beb 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -333,7 +333,7 @@
         key_type = mbedtls_psa_translate_cipher_type(
             ctx->cipher_info->type );
         if( key_type == 0 )
-            return( MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED );
+            return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
         status = psa_import_key( cipher_psa->slot,
                                  key_type, key, key_bytelen );
         if( status != PSA_SUCCESS )