Restructure usb_sg_cancel() so we don't have to disable interrupts
while cancelling the URBs.
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: David Mosberger <davidm@egauge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>