[SCSI] trivial scsi_execute_async fix

In scsi_execute_async()'s error path, a struct scsi_io_context
allocated with kmem_cache_alloc() is kfree()'d. Obviously
kmem_cache_free() should be used instead.
Signed-off-by: NArne Redlich <arne.redlich@xiranet.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_lib.c

@@ -424,7 +424,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
 free_req:
 	blk_put_request(req);
 free_sense:
-	kfree(sioc);
+	kmem_cache_free(scsi_io_context_cache, sioc);
 	return DRIVER_ERROR << 24;
 }
 EXPORT_SYMBOL_GPL(scsi_execute_async);