PCI: Separate pci_bus_read_dev_vendor_id from pci_scan_device

We can reuse it for pciehp probing.

-v2: according to Kenji, fix crs timeout checking, and export the function
     for later use when pciehp is compiled as a module.

Suggested-by: Matthew Wilcox <[email protected]>
Signed-off-by: Yinghai Lu <[email protected]>
Signed-off-by: Jesse Barnes <[email protected]>
2 files changed