ANDROID: KVM: arm64: Call __pkvm_host_share_guest on memory abort

Now that EL2 is ready to manage guest page-tables in protected mode, use
the recently introduced hypercall to share pages with guests from the
memory abort path, instead of manipulating their page-tables directly.

Signed-off-by: Quentin Perret <qperret@google.com>
Bug: 209580772
Change-Id: I05ed8283d0eed19b2cfd6314cfcafbe3f689937c
Signed-off-by: Will Deacon <willdeacon@google.com>