crypto: xts - Handle EBUSY correctly

In the Linux kernel, the following vulnerability has been resolved:

crypto: xts - Handle EBUSY correctly

As it is xts only handles the special return value of EINPROGRESS, which means that in all other cases it will free data related to the request.

However, as the caller of xts may specify MAY_BACKLOG, we also need to expect EBUSY and treat it in the same way. Otherwise backlogged requests will trigger a use-after-free.