drm/etnaviv: use PLATFORM_DEVID_NONE

There is already a macro for the magic value. Use it.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_drv.c

@@ -653,7 +653,7 @@ static int __init etnaviv_init(void)
 		if (!of_device_is_available(np))
 			continue;
 
-		pdev = platform_device_alloc("etnaviv", -1);
+		pdev = platform_device_alloc("etnaviv", PLATFORM_DEVID_NONE);
 		if (!pdev) {
 			ret = -ENOMEM;
 			of_node_put(np);