nvme/ioctl: don't warn on vectorized uring_cmd with fixed buffer

The vectorized io_uring NVMe passthru opcodes don't yet support fixed
buffers. But since userspace can trigger this condition based on the
io_uring SQE parameters, it shouldn't cause a kernel warning.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Fixes: 23fd22e55b ("nvme: wire up fixed buffer support for nvme passthrough")
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/ioctl.c

@@ -142,7 +142,7 @@ static int nvme_map_user_request(struct request *req, u64 ubuffer,
 		struct iov_iter iter;
 
 		/* fixedbufs is only for non-vectored io */
-		if (WARN_ON_ONCE(flags & NVME_IOCTL_VEC)) {
+		if (flags & NVME_IOCTL_VEC) {
 			ret = -EINVAL;
 			goto out;
 		}