iwlwifi: configure transport layer from dvm op mode

Introduce the iwl_trans_config struct which contains
state variables that only the op mode can determine,
but which the transport layer needs to know.

Signed-off-by: Meenakshi Venkataraman <meenakshi.venkataraman@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>