iommu: Add static iommu_ops->release_domain

The current device_release callback for individual iommu drivers does the
following:

1) Silent IOMMU DMA translation: It detaches any existing domain from the
   device and puts it into a blocking state (some drivers might use the
   identity state).
2) Resource release: It releases resources allocated during the
   device_probe callback and restores the device to its pre-probe state.

Step 1 is challenging for individual iommu drivers because each must check
if a domain is already attached to the device. Additionally, if a deferred
attach never occurred, the device_release should avoid modifying hardware
configuration regardless of the reason for its call.

To simplify this process, introduce a static release_domain within the
iommu_ops structure. It can be either a blocking or identity domain
depending on the iommu hardware. The iommu core will decide whether to
attach this domain before the device_release callback, eliminating the
need for repetitive code in various drivers.

Consequently, the device_release callback can focus solely on the opposite
operations of device_probe, including releasing all resources allocated
during that callback.

Co-developed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

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