ANDROID: KVM: arm64: Don't force pte mappings in [n]VHE guest stage-2

Commit d096d354 ("ANDROID: KVM: arm64: Have different callbacks for
PTE manipulation") accidentally forces the use of pte-level mappings for
the guest stage-2 page-table when not using pKVM.

This confuses user_mem_abort() when the guest takes a permission fault
trying to execute from a huge page. Since the fault is reported at the
pte-level, we end up handling it as a translation fault by calling
kvm_pgtable_stage2_map() which dutifully returns -EAGAIN when it finds
the RW PTE. Consequently, the guest appears to hang randomly during boot.

Fix the issue by inverting stage2_force_pte_cb() so that the host is in
complete control of the mapping granularity of the guest when pKVM is
not being used.

Cc: Fuad Tabba <tabba@google.com>
Cc: Mostafa Saleh <smostafa@google.com>
Fixes: d096d354 ("ANDROID: KVM: arm64: Have different callbacks for PTE manipulation")
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 222044487
Change-Id: Ideab281ae6d1d5c0fd29fba03ad8ed1cae521a1e