iwlagn: implement advance BT config command

6000g2b hardware implements advance bluetooth coexist command,
implement base on the new API command strucutre.

Also increment the API 5 to support the advance BT/WIfi coex.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>