Use only `MBEDTLS_ECP_WITH_MPI_UINT` to switch between the ecp variants

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index 03bbab6..0b4cd4b 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1636,12 +1636,10 @@
 {
     mbedtls_ecp_variant variant = mbedtls_ecp_get_variant();
 
-#if defined(MBEDTLS_ECP_WITH_MPI_STRUCT)
-    TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT);
-#elif defined(MBEDTLS_ECP_WITH_MPI_UINT)
+#if defined(MBEDTLS_ECP_VARIANT_WITH_MPI_UINT)
     TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_UINT);
 #else
-    #error "No ecp variant detected."
+    TEST_EQUAL(variant, MBEDTLS_ECP_VARIANT_WITH_MPI_STRUCT);
 #endif
 }
 /* END_CASE */