Revert "vhost: block speculation of translated descriptors"

This reverts commit a89db44.

I was hasty to include this patch, and it breaks the build on 32 bit.
Defence in depth is good but let's do it properly.

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.c

@@ -2071,10 +2071,8 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
 		_iov = iov + ret;
 		size = node->size - addr + node->start;
 		_iov->iov_len = min((u64)len - s, size);
-		_iov->iov_base = (void __user *)
-			((unsigned long)node->userspace_addr +
-			 array_index_nospec((unsigned long)(addr - node->start),
-					    node->size));
+		_iov->iov_base = (void __user *)(unsigned long)
+			(node->userspace_addr + addr - node->start);
 		s += size;
 		addr += size;
 		++ret;