usb: ehci-mxc: check for pdata before dereferencing

commit f375fc52 upstream.

Commit 7e8d5cd9 ("USB: Add EHCI support for MX27 and MX31 based
boards") introduced code that could potentially lead to a NULL pointer
dereference on driver removal.

Fix this by checking for the value of pdata before dereferencing it.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/host/ehci-mxc.c

@@ -296,7 +296,7 @@ static int __exit ehci_mxc_drv_remove(struct platform_device *pdev)
 	if (pdata && pdata->exit)
 		pdata->exit(pdev);
 
-	if (pdata->otg)
+	if (pdata && pdata->otg)
 		otg_shutdown(pdata->otg);
 
 	usb_remove_hcd(hcd);