lime.wireless: Fix wireless.is5Ghz

[pony1k]

Fix #1063, where wireless.is5Ghz returns true for the 2GHz radio on TP-LINK TD-W8970.

[codecov-commenter]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (d0c498f) 79.69% compared to head (ce17f08) 79.71%.
Report is 6 commits behind head on master.

❗ Current head ce17f08 differs from pull request most recent head 0c5b5d5. Consider uploading reports for the commit 0c5b5d5 to get more accurate results

Files	Patch %	Lines
...es/lime-system/files/usr/lib/lua/lime/wireless.lua	81.81%	2 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1071      +/-   ##
==========================================
+ Coverage   79.69%   79.71%   +0.01%     
==========================================
  Files          53       53              
  Lines        4550     4559       +9     
==========================================
+ Hits         3626     3634       +8     
- Misses        924      925       +1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[pony1k]

@G10h4ck Are you okay with this?

[G10h4ck]

Looks good to me