Fix time comparison math

Dividing `dt` here by 1e6 converts it to seconds, but that is clearly
wrong since `REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY` is measured
in microseconds.  As a result, this if statement was effectively never
used.

src/cryptonote_protocol/cryptonote_protocol_handler.inl

@@ -1673,9 +1673,9 @@ skip:
             const float max_multiplier = 10.f;
             const float min_multiplier = 1.25f;
             float multiplier = max_multiplier;
-            if (dt/1e6 >= REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY)
+            if (dt >= REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY)
             {
-              multiplier = max_multiplier - (dt/1e6-REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY) * (max_multiplier - min_multiplier) / (REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD - REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY);
+              multiplier = max_multiplier - (dt-REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY) * (max_multiplier - min_multiplier) / (REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD - REQUEST_NEXT_SCHEDULED_SPAN_THRESHOLD_STANDBY);
               multiplier = std::min(max_multiplier, std::max(min_multiplier, multiplier));
             }
             if (dl_speed * .8f > ctx.m_current_speed_down * multiplier)