kselftest/vDSO: Use ksft_print_msg() rather than printf in vdso_test_abi

There are a couple of raw printf() calls in vdso_test_abi which result in
non KTAP conforment output such as

   [vDSO kselftest] VDSO_VERSION: LINUX_2.6

Convert them to use ksft_print_msg() so that they don't cause confusion for
parsers.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/vDSO/vdso_test_abi.c

@@ -187,14 +187,14 @@ int main(int argc, char **argv)
 	ksft_set_plan(VDSO_TEST_PLAN);
 
 	if (!sysinfo_ehdr) {
-		printf("AT_SYSINFO_EHDR is not present!\n");
+		ksft_print_msg("AT_SYSINFO_EHDR is not present!\n");
 		return KSFT_SKIP;
 	}
 
 	version = versions[VDSO_VERSION];
 	name = (const char **)&names[VDSO_NAMES];
 
-	printf("[vDSO kselftest] VDSO_VERSION: %s\n", version);
+	ksft_print_msg("[vDSO kselftest] VDSO_VERSION: %s\n", version);
 
 	vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));