Add PNP info to xl as an example.

sys/dev/xl/if_xl.c

@@ -334,6 +334,8 @@ static devclass_t xl_devclass;
 DRIVER_MODULE_ORDERED(xl, pci, xl_driver, xl_devclass, NULL, NULL,
     SI_ORDER_ANY);
 DRIVER_MODULE(miibus, xl, miibus_driver, miibus_devclass, NULL, NULL);
+MODULE_PNP_INFO("U16:vendor;U16:device;D:#", pci, xl, xl_devs, sizeof(xl_devs[0]),
+    nitems(xl_devs) - 1);
 
 static void
 xl_dma_map_addr(void *arg, bus_dma_segment_t *segs, int nseg, int error)