T-API: minor optimization of morphology operations

**Description:**
* added new data types
* optimized the kernel by generating necessary computations. This trick eliminates additional synchronization when kernel should be copied to GPU memory.

**Performance report:**
http://ocl.itseez.com/intel/export/perf/pr/2867/report/

check_regression=*OCL*Erode*:*OCL*Dilate*:*OCL*Morph*
test_filter=*OCL*Erode*:*OCL*Dilate*:*OCL*Morph*
test_modules=imgproc
build_examples=OFF