Stop propagating MMU large page support into a memslot's disallow_lpage
now that the MMU's max_page_level handles the scenario where VMX's EPT is
enabled and EPT doesn't support 2M pages.

No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>