staging: dgrp: remove redundant NULL check before unregister_dgrp_device().

unregister_dgrp_device on a NULL pointer is a no-op, so the NULL checks in
dgrp_remove_nd() can be removed.
Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgrp/dgrp_specproc.c

@@ -777,14 +777,11 @@ static int dgrp_remove_nd(struct nd_struct *nd)
 		dgrp_remove_node_class_sysfs_files(nd);
 	}
 
-	if (nd->nd_mon_de)
-		unregister_dgrp_device(nd->nd_mon_de);
+	unregister_dgrp_device(nd->nd_mon_de);
 
-	if (nd->nd_ports_de)
-		unregister_dgrp_device(nd->nd_ports_de);
+	unregister_dgrp_device(nd->nd_ports_de);
 
-	if (nd->nd_dpa_de)
-		unregister_dgrp_device(nd->nd_dpa_de);
+	unregister_dgrp_device(nd->nd_dpa_de);
 
 	dgrp_tty_uninit(nd);