iwlagn: transport layer should receive iwl_trans

Change a lot of functions to have them receive iwl_trans and not iwl_priv.

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>