[FS#508] ath9k / poor performance + drops with r3426 (after airtime-fairness fixup)

[LEDE Bugs]

The following task has a new comment added:

FS#508 - ath9k / poor performance + drops with r3426 (after airtime-fairness fixup)
User who did this - Felix Fietkau (nbd)

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Fixed in r3421-764cd09dd8
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=508#comment1824