usb: host: xhci: fix compilation error for non-PCI based stacks

For non PCI-based stacks, this function call
usb_disable_xhci_ports(to_pci_dev(hcd->self.controller));
made from xhci_shutdown is not applicable.

Ideally, we wouldn't have any PCI-specific code on
a generic driver such as the xHCI stack, but it looks
like we should just stub usb_disable_xhci_ports() out
for non-PCI devices.

[ balbi@ti.com: slight improvement to commit log ]

This patch should be backported to kernels as old as 3.0, since the
commit it fixes (e95829f "xhci: Switch
PPT ports to EHCI on shutdown.") was marked for stable.

Signed-off-by: Moiz Sonasath<m-sonasath@ti.com>
Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

drivers/usb/host/pci-quirks.h

@@ -15,6 +15,7 @@ void usb_disable_xhci_ports(struct pci_dev *xhci_pdev);
 static inline void usb_amd_quirk_pll_disable(void) {}
 static inline void usb_amd_quirk_pll_enable(void) {}
 static inline void usb_amd_dev_put(void) {}
+static inline void usb_disable_xhci_ports(struct pci_dev *xhci_pdev) {}
 #endif  /* CONFIG_PCI */
 
 #endif  /*  __LINUX_USB_PCI_QUIRKS_H  */