usb: host: ehci-msm: Conditionally call ehci suspend/resume

This patch fixes a suspend/resume issue where the driver is blindly
calling ehci_suspend/resume functions when the ehci hasn't been setup.
This results in a crash during suspend/resume operations.
Signed-off-by: Andy Gross <andy.gross@linaro.org>
Tested-by: Pramod Gurav <pramod.gurav@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-msm.c

@@ -179,22 +179,32 @@ static int ehci_msm_remove(struct platform_device *pdev)
 static int ehci_msm_pm_suspend(struct device *dev)
 {
 	struct usb_hcd *hcd = dev_get_drvdata(dev);
+	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
 	bool do_wakeup = device_may_wakeup(dev);
 
 	dev_dbg(dev, "ehci-msm PM suspend\n");
 
+	/* Only call ehci_suspend if ehci_setup has been done */
+	if (ehci->sbrn)
 		return ehci_suspend(hcd, do_wakeup);
+
+	return 0;
 }
 
 static int ehci_msm_pm_resume(struct device *dev)
 {
 	struct usb_hcd *hcd = dev_get_drvdata(dev);
+	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
 
 	dev_dbg(dev, "ehci-msm PM resume\n");
+
+	/* Only call ehci_resume if ehci_setup has been done */
+	if (ehci->sbrn)
 		ehci_resume(hcd, false);
 
 	return 0;
 }
+
 #else
 #define ehci_msm_pm_suspend	NULL
 #define ehci_msm_pm_resume	NULL