Select ARCH_WANT_IRQS_OFF_ACTIVATE_MM so that activate_mm() is called with
irqs disabled. This allows to call switch_mm_irqs_off() instead of
switch_mm() and saves two local_irq_save() / local_irq_restore() pairs.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>