selftests/harness: Update named initializer syntax

The harness was still using old-style GNU named initializer syntax.
Fix this so Clang will stop warning:

seccomp_bpf.c:2924:1: warning: use of GNU old-style field designator extension
[-Wgnu-designator]
./../kselftest_harness.h:147:25: note: expanded from macro 'TEST'
^
./../kselftest_harness.h:172:5: note: expanded from macro '__TEST_IMPL'
fn: &test_name, termsig: _signal }; \
^

Signed-off-by: Kees Cook <[e-mail]>
Reviewed-by: Nick Desaulniers <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/kselftest_harness.h

···
 #define __TEST_IMPL(test_name, _signal) \
 	static void test_name(struct __test_metadata *_metadata); \
 	static struct __test_metadata _##test_name##_object = \
-		{ name: "global." #test_name, \
-		  fn: &test_name, termsig: _signal }; \
+		{ .name = "global." #test_name, \
+		  .fn = &test_name, .termsig = _signal }; \
 	static void __attribute__((constructor)) _register_##test_name(void) \
 	{ \
 		__register_test(&_##test_name##_object); \
···
 	} \
 	static struct __test_metadata \
 		      _##fixture_name##_##test_name##_object = { \
-		name: #fixture_name "." #test_name, \
-		fn: &wrapper_##fixture_name##_##test_name, \
-		termsig: signal, \
+		.name = #fixture_name "." #test_name, \
+		.fn = &wrapper_##fixture_name##_##test_name, \
+		.termsig = signal, \
 	 }; \
 	static void __attribute__((constructor)) \
 			_register_##fixture_name##_##test_name(void) \