net/ncsi: use proper "mellanox" DT vendor prefix

"mlx" Devicetree vendor prefix is not documented and instead "mellanox"
should be used.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

net/ncsi/ncsi-manage.c

···
 	pdev = to_platform_device(dev->dev.parent);
 	if (pdev) {
 		np = pdev->dev.of_node;
-		if (np && of_get_property(np, "mlx,multi-host", NULL))
+		if (np && (of_get_property(np, "mellanox,multi-host", NULL) ||
+			   of_get_property(np, "mlx,multi-host", NULL)))
 			ndp->mlx_multi_host = true;
 	}