tc_wrap.py is failing due to use of string operation on bytes object

[rohit-mundra]

tc_wrap.py is using Popen to execute instructions and the output is in bytes, as no encoding being defined in the argument to Popen.

As the output is in bytes, the regex and split on bytes will fail, this requires the output must be decoded before consumption.

https://github.com/Mellanox/mlnx-tools/blob/mlnx_ofed/python/tc_wrap.py#L153

https://github.com/Mellanox/mlnx-tools/blob/mlnx_ofed/python/tc_wrap.py#L56