pass correct index to simd procedure calls (#805)

Add missing check of whether to use direct or indirect indexing for simd procedure calls.

fixes #804

modcc/printer/cprinter.cpp

@@ -567,7 +567,10 @@ void SimdPrinter::visit(AssignmentExpression* e) {
 }
 
 void SimdPrinter::visit(CallExpression* e) {
-    out_ << e->name() << "(index_";
+    if(is_indirect_index_)
+        out_ << e->name() << "(index_";
+    else
+        out_ << e->name() << "(i_";
     for (auto& arg: e->args()) {
         out_ << ", ";
         arg->accept(this);