Updates for SGX 2.17 reproducible build.

Signed-off-by: Zhang Lili <lili.z.zhang@intel.com>

SampleCode/SampleDNNL/Enclave/Enclave.cpp

@@ -39,7 +39,7 @@
 
 using namespace std;
 
-extern "C" void printf(const char *fmt, ...)
+extern "C" int printf(const char *fmt, ...)
 {
     char buf[300] = {'\0'};
     va_list ap;
@@ -47,6 +47,8 @@ extern "C" void printf(const char *fmt, ...)
     vsnprintf(buf, BUFSIZ, fmt, ap);
     va_end(ap);
     ocall_print_string(buf);
+
+    return 0;
 }