mac80211: fix some more kernel-doc in mesh

Add a few more missing kernel-doc annotations in mesh code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200928135129.6409460c28b7.I43657d0b70398723e59e4e724f56af88af0fec7e@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>