scsi: virtio_scsi: Remove unnecessary condition check

kmem_cache_destroy() and mempool_destroy() both correctly handle null
pointer parameters. There is no need to check if the parameter is null
before calling these functions.

Link: https://lore.kernel.org/r/1594307167-8807-1-git-send-email-xianting_tian@126.comReviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/virtio_scsi.c

@@ -1002,14 +1002,10 @@ static int __init init(void)
 	return 0;
 
 error:
-	if (virtscsi_cmd_pool) {
 	mempool_destroy(virtscsi_cmd_pool);
 	virtscsi_cmd_pool = NULL;
-	}
-	if (virtscsi_cmd_cache) {
 	kmem_cache_destroy(virtscsi_cmd_cache);
 	virtscsi_cmd_cache = NULL;
-	}
 	return ret;
 }