KVM: PPC: e500: Mark "struct page" pfn accessed before dropping mmu_lock

Mark pages accessed before dropping mmu_lock when faulting in guest memory
so that shadow_map() can convert to kvm_release_faultin_page() without
tripping its lockdep assertion on mmu_lock being held.  Marking pages
accessed outside of mmu_lock is ok (not great, but safe), but marking
pages _dirty_ outside of mmu_lock can make filesystems unhappy.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-54-seanjc@google.com>