[FS#627] rt2x00: mt7620 channel regression

[LEDE Bugs]

The following task has a new comment added:

FS#627 - rt2x00: mt7620 channel regression
User who did this - Denis Mysenko (dusterio)

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Christian is right - I had issue with channels 10+ (similar behaviour - SSID would stop broadcasting, no errors given anywhere), but switching the mode to HT40 seems to have fixed the issue
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=627#comment2232