drm/virtio: Set segment size for virtio_gpu device

Set the segment size of the virtio_gpu device to the value
used by the drm helpers when allocating sg lists to fix the
following complaint from DMA_API debug code:

DMA-API: virtio-pci 0000:07:00.0: mapping sg segment longer than
device claims to support [len=262144] [max=65536]

Cc: stable@vger.kernel.org
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
Acked-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7258a4cc-da16-5c34-a042-2a23ee396d56@redhat.com

Author: Sebastian Ott

drivers/gpu/drm/virtio/virtgpu_drv.c

@@ -94,6 +94,7 @@ static int virtio_gpu_probe(struct virtio_device *vdev)
 			goto err_free;
 	}
 
+	dma_set_max_seg_size(dev->dev, dma_max_mapping_size(dev->dev) ?: UINT_MAX);
 	ret = virtio_gpu_init(vdev, dev);
 	if (ret)
 		goto err_free;