sd: bad return code of init_sd

In init_sd function, if kmem_cache_create or mempool_create_slab_pools
calls fail, the error will not be correclty reported because
class_register previously set the value of err to 0.
Signed-off-by: Clément Calmels <clement.calmels@free.fr>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/sd.c

@@ -3212,12 +3212,14 @@ static int __init init_sd(void)
 					 0, 0, NULL);
 	if (!sd_cdb_cache) {
 		printk(KERN_ERR "sd: can't init extended cdb cache\n");
+		err = -ENOMEM;
 		goto err_out_class;
 	}
 
 	sd_cdb_pool = mempool_create_slab_pool(SD_MEMPOOL_SIZE, sd_cdb_cache);
 	if (!sd_cdb_pool) {
 		printk(KERN_ERR "sd: can't init extended cdb pool\n");
+		err = -ENOMEM;
 		goto err_out_cache;
 	}