iwlwifi: implement iwl5000_calc_rssi

This patch implements rssi calculation for 5000 HW.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-core.h b/drivers/net/wireless/iwlwifi/iwl-core.h
index eaefa42..64f139e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-core.h
+++ b/drivers/net/wireless/iwlwifi/iwl-core.h
@@ -95,6 +95,8 @@
 	void (*chain_noise_reset)(struct iwl_priv *priv);
 	void (*rts_tx_cmd_flag)(struct ieee80211_tx_info *info,
 			__le32 *tx_flags);
+	int  (*calc_rssi)(struct iwl_priv *priv,
+			  struct iwl_rx_phy_res *rx_resp);
 };
 
 struct iwl_lib_ops {