use mygpu to determine GPU arch, get rid of cuda-gpu-arch and use mcpu, other simplifications, I think this makefile is still too complicated as an intro Makefile for HCC2
use mygpu to determine GPU arch, get rid of cuda-gpu-arch and use mcpu, other simplifications, I think this makefile is still too complicated as an intro Makefile for HCC2

ROCm-Developer-Tools/hcc2,ROCm-Developer-Tools/hcc2,ROCm-Developer-Tools/hcc2