iwlwifi: mvm: Free fw_status after use to avoid memory leak

fw_status is the only pointer pointing to a block of memory
allocated above and should be freed after use.
Note: this come from Klockwork static analyzer.

Cc: stable@vger.kernel.org [3.19+]
Fixes: 2021a89 ("iwlwifi: mvm: treat netdetect wake up separately")
Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/d3.c

@@ -1750,8 +1750,10 @@ static void iwl_mvm_query_netdetect_reasons(struct iwl_mvm *mvm,
 	int i, j, n_matches, ret;
 
 	fw_status = iwl_mvm_get_wakeup_status(mvm, vif);
-	if (!IS_ERR_OR_NULL(fw_status))
+	if (!IS_ERR_OR_NULL(fw_status)) {
 		reasons = le32_to_cpu(fw_status->wakeup_reasons);
+		kfree(fw_status);
+	}
 
 	if (reasons & IWL_WOWLAN_WAKEUP_BY_RFKILL_DEASSERTED)
 		wakeup.rfkill_release = true;