Regression in rtw89

[Larry Finger <Larry.Finger@xxxxxxxxxxxx>]

Ping-Ke,

A user of my GitHub repo has reported a regression beginning with commit 
26a125f550a3 ("wifi: rtw89: correct PS calculation for SUPPORTS_DYNAMIC_PS").
The user finds interference between wifi and the BT device that is part of the 
package.

We were able to determine that loading rtw89_core with the "disable_ps_mode=y" 
option does fix the problem. Our discussion of the problem can be seen at 
https://github.com/lwfinger/rtw89/issues/262#issuecomment-1664658764.

Reading the patch in question, it seems that a vif count of 1 is not sufficient 
to enable PS, and that it is also necessary to make sure that BT is not active 
as well.

Thanks,

Larry