KVM: arm64: Use correct accessor to parse stage-1 PTEs

hyp_get_page_state() is used with pKVM to retrieve metadata about a page
by parsing a hypervisor stage-1 PTE. However, it incorrectly uses a
helper which parses *stage-2* mappings. Ouch.

Luckily, pkvm_getstate() only looks at the software bits, which happen
to be in the same place for stage-1 and stage-2 PTEs, and this all ends
up working correctly by accident. But clearly, we should do better.

Fix hyp_get_page_state() to use the correct helper.

Fixes: e82edcc7 ("KVM: arm64: Implement do_share() helper for sharing memory")
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221025145156.855308-1-qperret@google.com