KVM: x86/xen: mark guest pages dirty with the pfncache lock held

KVM: x86/xen: mark guest pages dirty with the pfncache lock held

Sampling gpa and memslot from an unlocked pfncache may yield inconsistent
values so, since there is no problem with calling mark_page_dirty_in_slot()
with the pfncache lock held, relocate the calls in
kvm_xen_update_runstate_guest() and kvm_xen_inject_pending_events()
accordingly.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20240215152916.1158-4-paul@xen.org
Signed-off-by: Sean Christopherson <seanjc@google.com>