AMD/IOMMU: drop redundant code

The level 1 special exit path is unnecessary in iommu_pde_from_dfn() -
the subsequent code takes care of this case quite fine.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

xen/drivers/passthrough/amd/iommu_map.c

@@ -194,12 +194,6 @@ static int iommu_pde_from_dfn(struct domain *d, unsigned long dfn,
 
     next_table_mfn = mfn_x(page_to_mfn(table));
 
-    if ( level == 1 )
-    {
-        pt_mfn[level] = next_table_mfn;
-        return 0;
-    }
-
     while ( level > 1 )
     {
         unsigned int next_level = level - 1;