T-API: used built-in functions in core module

**Performance report:**
http://ocl.itseez.com/intel/export/perf/pr/2852/report/

check_regression=*OCL*Norm*:*OCL*MinMaxL*:*OCL*Add*:*OCL*Log*:*OCL*Abs*:*OCL*Patch*:*OCL*Polar*:*OCL*Scale*:*OCL*Sum*
test_filter=*OCL*Norm*:*OCL*MinMaxL*:*OCL*Add*:*OCL*Log*:*OCL*Abs*:*OCL*Patch*:*OCL*Polar*:*OCL*Scale*:*OCL*Sum*
test_modules=core
build_examples=OFF
This change makes unclear usage of this function. Please, stay API clear.