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 <[e-mail]>
Reviewed-by: Ewan D. Milne <[e-mail]>
Signed-off-by: Christoph Hellwig <[e-mail]>

drivers/scsi/sd.c

···
 					 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;
 	}