dm integrity: call kmem_cache_destroy() in dm_integrity_init() error path

Otherwise the journal_io_cache will leak if dm_register_target() fails.

Cc: [e-mail]
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-integrity.c

···
 	}
 
 	r = dm_register_target(&integrity_target);
-
-	if (r < 0)
+	if (r < 0) {
 		DMERR("register failed %d", r);
+		kmem_cache_destroy(journal_io_cache);
+		return r;
+	}
 
-	return r;
+	return 0;
 }
 
 static void __exit dm_integrity_exit(void)