iwlwifi: code cleanup for generic defines

Some defines used by all agn devices, but the definitions were in
iwl-4965-hw.h, move those to iwl-agn-hw.h which is the better place for
those.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
index 6e331f5..28bc8f8 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-hcmd.c
@@ -254,7 +254,7 @@
 
 	/* dBm = max_rssi dB - agc dB - constant.
 	 * Higher AGC (higher radio gain) means lower signal. */
-	return max_rssi - agc - IWL49_RSSI_OFFSET;
+	return max_rssi - agc - IWLAGN_RSSI_OFFSET;
 }
 
 struct iwl_hcmd_ops iwlagn_hcmd = {