iwlwifi: fix iwl4965 temperature callback calibration issue

The patch fixes the temperature calibration issue introduced by the
patch "iwlwifi: move RX stats to core, and move temperature to handler".
It also remove the second parameter "stats" since it is already copied
to priv->statistics.

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