mac80211: fix kernel-doc markups

      Some identifiers have different names between their prototypes
and the kernel-doc markup.

Others need to be fixed, as kernel-doc markups should use this format:
        identifier - description

In the specific case of __sta_info_flush(), add a documentation
for sta_info_flush(), as this one is the one used outside
sta_info.c.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Link: https://lore.kernel.org/r/978d35eef2dc76e21c81931804e4eaefbd6d635e.1603469755.git.mchehab+huawei@kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>