iwlagn: add documentation to the transport layer

and do a few clean up fixes on the way

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/iwlwifi/iwl-agn-tx.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-shared.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-trans.c
Simple merge