Fix integer division issue in int_to_percent function

Changed order of operations to preserve the precision during the division.
diff --git a/src/mixer.c b/src/mixer.c
index 742c231..e496e18 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -552,7 +552,7 @@
     if (range == 0)
         return 0;
 
-    return ((value - ei->value.integer.min) / range) * 100;
+    return ((value - ei->value.integer.min) * 100) / range;
 }
 
 /** Gets a percentage representation of a specified control value.