It could reduce 7 multiplications every iteration.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

1. Remove uncessary index calculation.
2. Use mad/mad24 as possible.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

1. decrease branch number in CL code by replacing them into weights
2. decrease local mem pressure in reduce operation by using private variables
3. decrease image sampler pressure by caching data into local memory
4. remove unnecessary sync point on the HOST side.

fix for cv::LUT and cv::transpose