FROMLIST: KVM: arm64: Fixup hyp stage-1 refcount

In nVHE-protected mode, the hyp stage-1 page-table refcount is broken
due to the lack of refcount support in the early allocator. Fix-up the
refcount in the finalize walker, once the 'hyp_vmemmap' is up and running.

Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20211201170411.1561936-5-qperret@google.com
Bug: 209599700
Change-Id: Ib31ace99838f397d7a2e48bfd43c6f4eaf730878