iwlagn: reduce redundant parameter definitions

move paramater definitions to a device paramater structure only
leaving the device name, which antennas are used and what firmware
file to use in the iwl_cfg structure.  this will not completely
remove the redundancies but greatly reduce them for devices that
only vary by name or antennas.  the parameters that are more
likely to change within a given device family are left in iwl_cfg.
also separate bt param structure added to help reduce more.

Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>