iwlwifi: keep track of bt coex enable/disable stage

For debugging purpose, keep track of the bt coex enable/disable state.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
index 7c8010f..4bc82fc 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-lib.c
@@ -1845,6 +1845,7 @@
 			bt_cmd.flags |= IWLAGN_BT_FLAG_CHANNEL_INHIBITION;
 		IWL_DEBUG_INFO(priv, "BT coex flag: 0X%x\n", bt_cmd.flags);
 	}
+	priv->bt_enable_flag = bt_cmd.flags;
 	if (priv->bt_full_concurrent)
 		memcpy(bt_cmd.bt3_lookup_table, iwlagn_concurrent_lookup,
 			sizeof(iwlagn_concurrent_lookup));