[PATCH 5.10 0/1] mt76: move mt76_init_tx_queue in common code

[Nikita Zhandarovich]

My apologies, I should've have explained my reasoning better.

1. My issue with 5.10 version of mt7615_init_tx_queues() in drivers/net/wireless/mediatek/mt76/mt7615/dma.c is that return value of final call to mt7615_init_tx_queue() is not taken into account
when returning result of mt7615_init_tx_queues(). So, if last mt7615_init_tx_queue() fails (due to memory issues, for instance), parent function will still erroneously return 0.

2. To correct the issue, I turned to Lorenzo's patch in b671da33d1c5973f90f098ff66a91953691df582 which solves my petit problem as well as rewrites a single mt76_init_tx_queue() function to be used
across all mt76 drivers.

3. I was torn between writing my own little patch to fix a single mistake or use an existing one that increases code readability and uniformity. I settled on latter.

4. As for this patch exclusivity to 5.10.y branch, I have an incentive to prioritise prioritize 5.10. Wasn't sure I should be the one to suggest the patch for other branches.

Thanks,

Nikita