I can attempt to test; however, there have been issues with "wifi speed" and packet loss when multiple clients are putting the wifi network under load (reported here and I think I observe similar symptoms here). I'm hoping today's patch from @nbd will resolve that so I'd like to test with and without your patch from the current head of master (via a cherry pick) if that works. If not, please let me know.
EDIT: It builds, loads, and is running (I verified that a few of the changes in your commit are in the build dir). I'll let it go for a day or so.
I still see the wifi issue I observed before this build for multiple clients putting the wifi network under load (so @nbd's patch must be unrelated to that issue); however, irtt/netperf for only one wifi client at a time seem fine (at least the same as before).
EDIT1: After 24 hr up with this commit on the r7500v2 configured as an AP only, I haven't observed a significant difference from prior builds.
git log
74f3dac4f057 Ansuel Smith Sat Aug 8 16:50:04 2020 +0200 ipq806x: replace pci patchset with upstream version
17d16e093f4a Josef Schlehofer Fri Aug 21 17:17:47 2020 +0200 curl: update to version 7.72.0
9c5128854eaf Felix Fietkau Fri Aug 21 20:44:25 2020 +0200 kernel: backport a fix for a regression that broke IRQ affinity on ARM
010682067b65 Felix Fietkau Fri Aug 21 18:06:50 2020 +0200 mac80211: add missing return code checks in AQL improvements
...
r7500v2 # uname -a
Linux r7500v2 5.4.59 #0 SMP Sat Aug 22 03:12:38 2020 armv7l GNU/Linux
r7500v2 # uptime
08:44:04 up 1 day, 37 min, load average: 0.00, 0.05, 0.06