hipcc: HCC workaround no longer needs env var
hipcc: HCC workaround no longer needs env var

Change-Id: I81f4eafddbda5e9e2f1082932dd502ab451cfc24

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