ixgbe: don't check NULL for debugfs_remove_recursive

The debugfs_remove_recursive function is NULL-safe, so we don't need to
check here ourselves.
Signed-off-by: NJacob Keller <jacob.e.keller@intel.com>
Tested-by: NPhil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_debugfs.c

@@ -253,8 +253,7 @@ void ixgbe_dbg_adapter_init(struct ixgbe_adapter *adapter)
  **/
 void ixgbe_dbg_adapter_exit(struct ixgbe_adapter *adapter)
 {
-	if (adapter->ixgbe_dbg_adapter)
-		debugfs_remove_recursive(adapter->ixgbe_dbg_adapter);
+	debugfs_remove_recursive(adapter->ixgbe_dbg_adapter);
 	adapter->ixgbe_dbg_adapter = NULL;
 }