pcic.4: Remove stale manual

Approved by: re (cperciva)
MFC after: 2 days (squashed with fixup commit)
Reviewed by: ziaee
Fixes: 31b35400c (pccard: Remove more of the PC Card)
Discussed with: bsdimp, emaste, jhb
Extracted from: https://reviews.freebsd.org/D53434

(cherry picked from commit 1d9f2db7c0b981bf5d45e3ef17dda13b953e1c97)
(cherry picked from commit 6aaf184dc4e294779db7133629b7ae953b4da285)
(cherry picked from commit feb8971db4b179d90b7cd006c43421fdaf4dbf7f)