genesys: silence compiler warning related to unused parameters

backend/genesys/image.cpp

@@ -216,6 +216,9 @@ void write_tiff_file(const std::string& filename, const void* data, int depth, i
     TIFFClose(image);
 
 #else
+    (void)data;
+    (void)filename;
+    
     dbg.log(DBG_error, "Backend has been built without TIFF library support. "
             "Debug images will not be saved");
 #endif