drm/virtio: Return proper error codes instead of -1

Don't return -1 in error cases, return proper error code. The returned
error codes propagate to error messages and to userspace and it's always
good to have a meaningful error number for debugging purposes.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

drivers/gpu/drm/virtio/virtgpu_vq.c

@@ -320,7 +320,7 @@ static int virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
 		if (fence && vbuf->objs)
 			virtio_gpu_array_unlock_resv(vbuf->objs);
 		free_vbuf(vgdev, vbuf);
-		return -1;
+		return -ENODEV;
 	}
 
 	if (vgdev->has_indirect)
@@ -384,7 +384,7 @@ static int virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
 			if (!sgt) {
 				if (fence && vbuf->objs)
 					virtio_gpu_array_unlock_resv(vbuf->objs);
-				return -1;
+				return -ENOMEM;
 			}
 
 			elemcnt += sg_ents;
@@ -750,7 +750,7 @@ static int virtio_get_edid_block(void *data, u8 *buf,
 	size_t start = block * EDID_LENGTH;
 
 	if (start + len > le32_to_cpu(resp->size))
-		return -1;
+		return -EINVAL;
 	memcpy(buf, resp->edid + start, len);
 	return 0;
 }