iommu/vt-d: Fix NULL domain on device release

In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Fix NULL domain on device release

In the kdump kernel, the IOMMU operates in deferred_attach mode. In this

mode, info->domain may not yet be assigned by the time the release_device

function is called. It leads to the following crash in the crash kernel:

BUG: kernel NULL pointer dereference, address: 000000000000003c

...

RIP: 0010:do_raw_spin_lock+0xa/0xa0

...

_raw_spin_lock_irqsave+0x1b/0x30

intel_iommu_release_device+0x96/0x170

iommu_deinit_device+0x39/0xf0

__iommu_group_remove_device+0xa0/0xd0

iommu_bus_notifier+0x55/0xb0

notifier_call_chain+0x5a/0xd0

blocking_notifier_call_chain+0x41/0x60

bus_notify+0x34/0x50

device_del+0x269/0x3d0

pci_remove_bus_device+0x77/0x100

p2sb_bar+0xae/0x1d0

...

i801_probe+0x423/0x740

Use the release_domain mechanism to fix it. The scalable mode context

entry which is not part of release domain should be cleared in

release_device().