xhci: Reset controller on xhci shutdown

Fixes kexec boot. Without a hard reset, some USB chips will fail to
initialize in a kexec booted kernel.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

drivers/usb/host/xhci.c

@@ -793,6 +793,9 @@ void xhci_shutdown(struct usb_hcd *hcd)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
 			"xhci_shutdown completed - status = %x",
 			readl(&xhci->op_regs->status));
+
+	/* TI XHCI controllers do not come back after kexec without this hack */
+	pci_reset_function_locked(to_pci_dev(hcd->self.sysdev));
 }
 EXPORT_SYMBOL_GPL(xhci_shutdown);