Fix casting from/to int/float that caused lot of compiler warnings.

modules/features2d/src/akaze.cpp

@@ -30,12 +30,12 @@ namespace cv
             if (descriptor_size == 0)
             {
                 int t = (6 + 36 + 120) * descriptor_channels;
-                return ceil(t / 8.);
+                return (int)ceil(t / 8.);
             }
             else
             {
                 // We use the random bit selection length binary descriptor
-                return ceil(descriptor_size / 8.);
+                return (int)ceil(descriptor_size / 8.);
             }
         }
     }