iwlwifi: add WOWLAN uCode loading support by testmode

Create new tm command for WOWLAN uCode loading to support
further debugging function in userspace.

- IWL_TM_CMD_APP2DEV_LOAD_WOWLAN_FW

Signed-off-by: Kenny Hsu <kenny.hsu@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>