x86/p2m-pt: ignore pt-share flag for shadow mode guests

There is no page table sharing in shadow mode.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
This was split out from a previously submitted patch.

--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -645,7 +646,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
 
     if ( iommu_enabled && need_iommu(p2m->domain) )
     {
-        if ( iommu_hap_pt_share )
+        if ( iommu_use_hap_pt(p2m->domain) )
         {
             if ( old_mfn && (old_mfn != mfn_x(mfn)) )
                 amd_iommu_flush_pages(p2m->domain, gfn, page_order);