iommu/vt-d: Move QI initializationt to intel_setup_irq_remapping

QI needs to be enabled when we program the irq remapping
table to hardware in the prepare phase later.

Tested-by: ZhenHua Li <zhen-hual@hp.com>
Tested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>