PCI: Log device type during enumeration

Log the device type when enumeration a device.  Sample output changes:

  - pci 0000:00:00.0: [8086:1237] type 00 class 0x060000
  + pci 0000:00:00.0: [8086:1237] type 00 class 0x060000 conventional PCI endpoint

  - pci 0000:00:1c.0: [8086:a110] type 01 class 0x060400
  + pci 0000:00:1c.0: [8086:a110] type 01 class 0x060400 PCIe Root Port

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>