Convert curve 448 to use ecp core functions

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index f034d6f..95aaef2 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1499,7 +1499,7 @@
     TEST_LE_U(X.n, 2 * limbs);
     TEST_EQUAL(res.n, limbs);
 
-    TEST_EQUAL(mbedtls_ecp_mod_p448(&X), 0);
+    TEST_EQUAL(mbedtls_ecp_mod_p448(X.p, X.n), 0);
     TEST_EQUAL(mbedtls_mpi_mod_mpi(&X, &X, &N), 0);
     TEST_LE_U(mbedtls_mpi_core_bitlen(X.p, X.n), 448);
     ASSERT_COMPARE(X.p, bytes, res.p, bytes);