iwlwifi: make config const

Writing to the global config structures
is always wrong. To protect against such
mistakes in the future, mark them const.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.c b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
index 6915b33..f965ee3 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.c
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.c
@@ -512,7 +512,7 @@
  * iwl_get_max_txpower_avg - get the highest tx power from all chains.
  *     find the highest tx power from all chains for the channel
  */
-static s8 iwl_get_max_txpower_avg(struct iwl_cfg *cfg,
+static s8 iwl_get_max_txpower_avg(const struct iwl_cfg *cfg,
 		struct iwl_eeprom_enhanced_txpwr *enhanced_txpower,
 		int element, s8 *max_txpower_in_half_dbm)
 {