KMix: fixed rounding error on volume reading. This was preventing 1% volume increase steps from working properly.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit e1b2705c5d)

kmix/mixer.cpp

@@ -568,7 +568,9 @@ int Mixer::volume( int deviceidx )
   }
   else
   {
-     return ( vol.getVolume( Volume::LEFT )*100) / volumeRange ;
+     // Make sure to round correctly, otherwise the volume level will always be 1% too low
+     // and increments of 1% of top of the value read will result in no change to the actual level
+     return ((100.0 * vol.getVolume(Volume::LEFT) + volumeRange / 2) / volumeRange);
   }
 }