OCL: pyrUp

**Description:**
- unrolled kernel for 1-channel
- removed storing of zeros and multiplication by them

**Performance report:**
http://ocl.itseez.com/intel/export/perf/pr/2790/report/

check_regression=*OCL*yrUp*
build_examples=OFF
test_modules=imgproc
does it work if either `dst.rows` or `dst.cols` is odd?