Update documentation for hipEventCreateWithFlags
Update documentation for hipEventCreateWithFlags

Change-Id: I2658bd95df0d3a802cce4ffcb8dfd40e7055b0f7

ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP