physical: Cleanup unnecessary variables

Change-Id: Ib5897e4f7226993c2deb1feb6e2e39d5a0f0cb5a
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/physical.cpp b/physical.cpp
index 2b404b6..77d3d4f 100644
--- a/physical.cpp
+++ b/physical.cpp
@@ -31,14 +31,9 @@
     {
         // LED is blinking. Get the on and off delays and derive percent duty
         auto delayOn = led.getDelayOn();
-        auto delayOff = led.getDelayOff();
-
-        // Calculate duty from millisecond delay values and derive percentage on
-        periodMs = delayOn + delayOff;
-        auto factor = periodMs / 100;
-        auto dutyOn = delayOn / factor;
-
-        this->dutyOn(dutyOn);
+        periodMs = delayOn + led.getDelayOff();
+        auto percentScale = periodMs / 100;
+        this->dutyOn(delayOn / percentScale);
     }
     else
     {