On the removal stage we put a reference to the controller structure and
if it's not used anymore it gets freed, but later we try to dereference
a pointer to a member of that structure.

Copy necessary field to a temporary variable to avoid use after free.

Fixes: 306c54d0 ("usb: hcd: Try MSI interrupts on PCI devices")
Reported-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/linux-usb/30a8c4ca-64c2-863b-cfcd-0970599c0ba3@huawei.com/Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200814182218.71957-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>