mac80211: factor out 802.11 header building code
mac80211: factor out 802.11 header building code

Factor out the 802.11 header building code from the xmit function
to be able to use it separately in a later commit.

While at it, fix up some documentation.

Signed-off-by: Johannes Berg <bff32994ff0f8d048f262a8388145a71b6071bfe@intel.com>
Signed-off-by: Arik Nemtsov <1a5d131848a166677cc209f94fa988cee9378c32@wizery.com>
Signed-off-by: Johannes Berg <bff32994ff0f8d048f262a8388145a71b6071bfe@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs