wireless: docs: fix 'make pdfdocs' failure

'make pdfdocs' failed for 80211.tmpl and reported errors of the form:
'document type does not allow element "refentry" here'
Fix this by moving </section> tags to a location that makes sense,
this fixes the errors and the pdf looks OK in relevant areas.

Signed-off-by: Sharon Dvir <sharon.dvir1@mail.huji.ac.il>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>