iommu: intel: Use generic_iommu_put_resv_regions()

Use the new standard function instead of open-coding it.

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>