iwlwifi: use .cfg to enable/disable continuous ucode trace

Instead of checking device type for enable/disable continuous ucode
trace function; put it in .cfg for better control and more
flexibilities.

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-debugfs.c b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
index 0faadf3..59355fae1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-debugfs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-debugfs.c
@@ -1640,8 +1640,9 @@
 	if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) != CSR_HW_REV_TYPE_3945) {
 		DEBUGFS_ADD_FILE(sensitivity, dir_debug, S_IRUSR);
 		DEBUGFS_ADD_FILE(chain_noise, dir_debug, S_IRUSR);
-		DEBUGFS_ADD_FILE(ucode_tracing, dir_debug, S_IWUSR | S_IRUSR);
 	}
+	if (priv->cfg->ucode_tracing)
+		DEBUGFS_ADD_FILE(ucode_tracing, dir_debug, S_IWUSR | S_IRUSR);
 	DEBUGFS_ADD_FILE(rxon_flags, dir_debug, S_IWUSR);
 	DEBUGFS_ADD_FILE(rxon_filter_flags, dir_debug, S_IWUSR);
 	DEBUGFS_ADD_BOOL(disable_sensitivity, dir_rf, &priv->disable_sens_cal);