the legacy driver was dropped in linux 5.14-rc3:
commit d249ff28b1d8 ("intersil: remove obsolete prism54 wireless driver")
Quoting Lukas Bulwahn:
"p54 replaces prism54 so users should be unaffected."
Reported-by: Marius Dinu <m95d+git@psihoexpert.ro>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>