iwlwifi.4, rtw88.4, rtw89.4: Fix xref typos

MFC after: 3 days
Reviewed by: bz, ziaee
Fixes: 0a2f7683bf0c ("man: iwlwifi/rtw88/rtw89: update man pages for Linux v7.0 based updates")
Differential Revision: https://reviews.freebsd.org/D57720

(cherry picked from commit d036b3b348d3f7be21f79461d7ad48e97b088ba8)