ANDROID: KVM: iommu: Abstract hypercalls

At the moment, the SMMUv3 driver calls KVM IOMMU hypercalls directly,
that is not ideal as:
- It can be built as a module, which means the HVCs become part of KMI
- It duplicates some logic, for example, when mapping in the IOMMU,
  we want to keep calling the HVC and topping up the allocator in case
  of no memory, which is a common logic

So, move those outside of the driver in the KVM IOMMU kernel part.

Bug: 357781595
Change-Id: Ica2b682efe62429841642d4a947ac315770f7bb3
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>