KVM: MMU: Add memslot parameter to hva handlers

This is needed to push trace_kvm_age_page() into kvm_age_rmapp() in the
following patch.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>