iommu/vt-d: fix resource leakage on error recovery path in iommu_init_domains()

Release allocated resources on error recovery path in function
iommu_init_domains().

Also improve printk messages in iommu_init_domains().

Acked-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>