Sorry that it took so long to get back to you.I appreciate the time you've spent on this. I did try 6.4 again (6.4.1 actually) and wlan0 did eventually come active. When I tried this before, I probably got freaked by the number of WARNINGs when it wasn't connecting, but perhaps it was failing for some other reason. I didn't realize they were only warnings.
For my ppc32, there is no regression. It took a while to learn the pio=1 and qos=0 are BOTH needed. That I do not understand, but with both set, the device works with kernel 6.4 and all earlier kernels that I tried. Fortunately, I did not need to do the entire bisection.
I am working on eliminating the warning that appears with qos=0, but it does not inhibit operations.
@Bagas Sanjaya: Please mark this "regression" as invalid.
Larry