[FreeBSD] decode Error

### Step 1: Describe your environment

* System (Intel/AMD/Raspberry Pi etc): __Intel X86_64 Core Due 2___
* OS version: __FreeBSD 12.1___
* s-tui version: __latest on PIP3___
* Installation method(pip/PPA/source code): __pip || freebsd pkg both the same___

### Step 2: Describe the problem:

##s-tui
Traceback (most recent call last):
File "/usr/local/bin/s-tui", line 11, in
load_entry_point('s-tui==1.0.2', 'console_scripts', 's-tui')()
File "/usr/local/lib/python3.7/site-packages/s_tui/s_tui.py", line 903, in main
graph_controller = GraphController(args)
File "/usr/local/lib/python3.7/site-packages/s_tui/s_tui.py", line 715, in __init__
possible_sources = self._load_config(args.t_thresh)
File "/usr/local/lib/python3.7/site-packages/s_tui/s_tui.py", line 648, in _load_config
FreqSource(),
File "/usr/local/lib/python3.7/site-packages/s_tui/sources/freq_source.py", line 50, in __init__
self.top_freq = psutil.cpu_freq().max
File "/usr/local/lib/python3.7/site-packages/psutil/__init__.py", line 1877, in cpu_freq
ret = _psplatform.cpu_freq()
File "/usr/local/lib/python3.7/site-packages/psutil/_psbsd.py", line 454, in cpu_freq
current, available_freq = cext.cpu_frequency(cpu)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x80 in position 64: invalid start byte
## Observed Results: