[HIPIFY][cmake] Minor refactoring
[HIPIFY][cmake] Minor refactoring

1. Fix setting std c++ (11|14)
2. Get rid of WIN32, use MSVC instead
3. Use VERSION_GREATER_EQUAL and VERSION_MAJOR instead of logical expressions

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