linux: Fix platform device probe for DT-based PCI
On a DT-base PCI platform, the sysfs path of vga device is like this: /sys/devices/platform/bus@10000000/1a000000.pci/pci0000:00/0000:00:11.0/0000:04:00.0.
Then the ID_PATH from udev is platform-1a000000.pci-pci-0000:04:00.0 and the BusID will be pci-0000:04:00.0, which causes Xorg start fail. This is because config_udev_odev_setup_attribs() use strstr() to search the first "pci-" in ID_PATH. To fix this, we implement a strrstr() function and use it to search the last "pci-" in ID_PATH, which can get a correct BusID.
Signed-off-by: Huacai Chen email@example.com