config: Fix platform busid parsing when there is no ID_PATH prop
On at least Lenovo Thinkpad E585 udev does not have ID_PATH property for the drm node (see #993 (closed)). While this is likely udev bug, this causes the device to be not recognized as attribs->busid is NULL, which causes platform_find_pci_info to be not called and corresponding xf86_platform_devices[i]->pdev to be NULL.
At this moment pdev being NULL will cause a crash, but this is a different bug.
Fixes: #993 (closed)
Fixes: 0816e8fc linux: Make platform device probe less fragile
Edited by Povilas Kanapickas