PCI: Override Synopsys USB 3.x HAPS device class

Synopsys USB 3.x host HAPS platform has a class code of
PCI_CLASS_SERIAL_USB_XHCI, and xhci driver can claim it.  However, these
devices should use dwc3-haps driver.  Change these devices' class code to
PCI_CLASS_SERIAL_USB_DEVICE to prevent the xhci-pci driver from claiming
them.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>