utask->xol_vaddr is either zero or valid, remove the bogus
IS_ERR_VALUE() check in xol_free_insn_slot().
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Acked-by: NAnton Arapov <anton@redhat.com>
Acked-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>