ANDROID: Add new pkvm_iommu_* functions to aarch64 ABI

Add two new symbols to aarch64 kernel ABI:
  * pkvm_iommu_sysmmu_sync_register
  * pkvm_iommu_finalize

The former allows vendor modules to register a SYSMMU_SYNC device with
the hypervisor, and the latter tells the hypervisor to stop acception
new device registrations.

Bug: 190463801
Signed-off-by: David Brazdil <dbrazdil@google.com>
Change-Id: I6c6948d94cb6494f07d52b4e2b7e91db40e2fcd6