[BUG] code bug

[BaiStone2017]

In benchmarks/python/mem_monitor.py

def get_memory_info(handle):
    mem_info = pynvml.nvmlDeviceGetMemoryInfo(handle)
    total = round(mem_info.total / 1024 / 1024 / 1024, 2)
    used = round(mem_info.used / 1024 / 1024 / 1024, 2)
    free = round(mem_info.used / 1024 / 1024 / 1024, 2)
    return total, used, free

For 'free' in line 5, should be 'mem_info.free'

[byshiue]

Thank you for report. We will fix it ASAP.