Remove useless parameter iret for ecp mul_inv cases

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>
diff --git a/tests/suites/test_suite_ecp.function b/tests/suites/test_suite_ecp.function
index bc2cd75..02afecd 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -1552,7 +1552,7 @@
 /* END_CASE */
 
 /* BEGIN_CASE depends_on:MBEDTLS_TEST_HOOKS */
-void ecp_mod_mul_inv(char *input_A, int id, int ctype, int iret)
+void ecp_mod_mul_inv(char *input_A, int id, int ctype)
 {
     size_t limbs;
     mbedtls_mpi_mod_modulus m;
@@ -1565,8 +1565,6 @@
     mbedtls_mpi_uint *bufx = NULL;
     const mbedtls_mpi_uint one[2] = {1, 0};
 
-    ((void) iret);
-
     mbedtls_mpi_mod_modulus_init(&m);
 
     TEST_ASSERT(mbedtls_ecp_modulus_setup(&m, id, ctype) == 0);