minor ocl.cpp refactoring

fix for cv::LUT and cv::transpose

modules/video/src/opencl/optical_flow_farneback.cl

@@ -142,11 +142,6 @@ inline int idx_row_high(const int y, const int last_row)
     return abs(last_row - abs(last_row - y)) % (last_row + 1);
 }
 
-inline int idx_row(const int y, const int last_row)
-{
-    return idx_row_low(idx_row_high(y, last_row), last_row);
-}
-
 inline int idx_col_low(const int x, const int last_col)
 {
     return abs(x) % (last_col + 1);
@@ -431,4 +426,4 @@ __kernel void updateFlow(__global const float * M, int mStep,
         flowx[mad24(y, xStep, x)] = (g11*h2 - g12*h1) * detInv;
         flowy[mad24(y, yStep, x)] = (g22*h1 - g12*h2) * detInv;
     }
-}
+}