[regression] Tri-band AMD RZ608 (MediaTek MT7921K) has 6GHz band disabled in kernel 6.8 despite working in <=6.6

[Linux regression tracking (Thorsten Leemhuis)]

Hi, Thorsten here, the Linux kernel's regression tracker.

mt7921 maintainers, I noticed a report about a regression in
bugzilla.kernel.org related to your driver. As many (most?) kernel
developers don't keep an eye on bugzilla, I decided to write this mail.
To quote from https://bugzilla.kernel.org/show_bug.cgi?id=218731 :

> On kernel 6.6.27-1-lts, running `iw list` shows that 6GHz channels are supported:>
> [...]
> Similarly, discovering and connecting to 6GHz APs works fine.
> 
> However, in recent kernel 6.8.5, running `iw list` shows that 6GHz channels are disabled:
>
> [...]
>
> And scanning or connecting to 6GHz APs does not work. 
> 
> There's nothing in `dmesg` that differs between boots of the two kernels. On 6.8.5, 6GHz band doesn't work like it did on previous kernels. 
> 
> I can provide more logs or help debug the issue if needed.

See the ticket for more details. Note, you have to use bugzilla to reach
the reporter, as I sadly[1] can not CCed them in mails like this.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

[1] because bugzilla.kernel.org tells users upon registration their
"email address will never be displayed to logged out users"

P.S.: let me use this mail to also add the report to the list of tracked
regressions to ensure it's doesn't fall through the cracks:

#regzbot introduced: v6.6..v6.8.5
#regzbot title: wifi drivers: mt7921: 6GHz band stopped working
#regzbot from: AlexDeLorenzo.dev
#regzbot duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=218731
#regzbot ignore-activity