Change hipcc to take HCC_HOME from hipconfig by default 1. Current implementation checks both env var and value in hipconfig and reports error 2. New implementation gives value in hipconfig with highest priority 3. If hipconfig is not present, fall back to env variables.
Change hipcc to take HCC_HOME from hipconfig by default
1. Current implementation checks both env var and value in hipconfig and reports error
2. New implementation gives value in hipconfig with highest priority
3. If hipconfig is not present, fall back to env variables.

To Devs: No need to switch between environment variables for different HCC + different HIP.

Change-Id: I6cdf37e1429d7f07be3a68c7e5ba1533d832962b

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