hipgenisa.sh: Honors ROCM_TARGET env or uses default
hipgenisa.sh: Honors ROCM_TARGET env or uses default

Change-Id: Idabf77ff1610ba4adbc78cfa69eb6e87d7e94ee9

ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP