ANDROID: KVM: arm64: Simplify np-guest hypercalls

Several of the hypercalls for managing the stage-2 page-table of NP
guests have no effect on the pKVM ownership tracking (wrprotect,
relax_perms, test_clear_young, mkyoung).

To simplify them, remove the __check_host_shared_guest() checks from
their implementations. That allows to drop the 'order' parameter from
several of them, and to avoid iteration over the pkvm_mapping list at
EL1, both of which simplify the integration with THP.

Bug: 357781595
Bug: 235345873
Change-Id: Ifc5e0ccfa146a2c8449fc8ee365ff78f0873a7cd
Signed-off-by: Quentin Perret <qperret@google.com>