Minor portability fix in benchmark

On embedded systems, argc might be 0 rather than 1 for no argument.
diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index 912aa7d..5dff3e9 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -255,8 +255,10 @@
     unsigned char malloc_buf[HEAP_SIZE] = { 0 };
 #endif
 
-    if( argc == 1 )
+    if( argc <= 1 )
+    {
         memset( &todo, 1, sizeof( todo ) );
+    }
     else
     {
         memset( &todo, 0, sizeof( todo ) );