iwlwifi: move setting up fw parameters

Gather parameters required to configure the
transport layer before invoking the transport
configuration API.

Change-Id: I5b39da284af6d9b5432a08911b4e1173a4d7207d
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>