iommu/arm: Don't allow the same micro-TLB to be shared between domains

iommu/arm: Don't allow the same micro-TLB to be shared between domains

For the IPMMU-VMSA we need to prevent the use cases where devices
which use the same micro-TLB are assigned to different Xen domains
(micro-TLB cannot be shared between multiple Xen domains, since it
points to the context bank to use for the page walk).

As each Xen domain uses individual context bank pointed by context_id,
we can potentially recognize that use case by comparing current and new
context_id for the already enabled micro-TLB and prevent different
context bank from being set.

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Acked-by: Julien Grall <julien@xen.org>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>