Fix Broken Link in hip_porting_guide (#1376)
Fix Broken Link in hip_porting_guide (#1376)

The math library equivalents between CUDA-HIP are broken. This is a key feature for converting to AMD hardware. This fix corrects the broken link and moves the library equivalents to sit under the "Porting a New Cuda Project" header.
GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP