Add initialization for structures

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 42d69b4..7d29e52 100644
--- a/tests/suites/test_suite_ecp.function
+++ b/tests/suites/test_suite_ecp.function
@@ -72,6 +72,9 @@
     size_t olen;
     unsigned char buf[42] = { 0 };
 
+    mbedtls_ecp_group_init( &grp );
+    mbedtls_ecp_point_init( &P );
+
     TEST_EQUAL( MBEDTLS_ERR_ECP_BAD_INPUT_DATA,
                             mbedtls_ecp_point_write_binary( &grp, &P,
                                                       invalid_fmt,