dm: remove duplicate module name from error msgs

Remove explicit module name from messages as the macro now includes it
automatically.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/dm-round-robin.c

@@ -205,7 +205,7 @@ static void __exit dm_rr_exit(void)
 	int r = dm_unregister_path_selector(&rr_ps);
 
 	if (r < 0)
-		DMERR("round-robin: unregister failed %d", r);
+		DMERR("unregister failed %d", r);
 }
 
 module_init(dm_rr_init);