KVM: MMU: change tracepoints arguments to kvm_page_fault

Pass struct kvm_page_fault to tracepoints instead of extracting the
arguments from the struct.  This also lets the kvm_mmu_spte_requested
tracepoint pick the gfn directly from fault->gfn, instead of using
the address.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>