iwmc3200wifi: Update statistics notification structure

The latest firmware adds a ht_rates and a chain_energy field. The latter is
needed as we want to eventually support RSSI/antenna handling.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>