It should also be better for optimizing when compiling kernel.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

1. Remove unnecessary barriers.
2. Adjust CTA_SIZE based on the following cases for Intel platform:
   a) OCL_Photo_DenoisingGrayscale.DenoisingGrayscale
   b) OCL_Photo_DenoisingColored.DenoisingColored