alloc_pdir() is called with smmu->as[?].pdir_page == NULL. No need to
check pdir_page again inside alloc_pdir().
Signed-off-by: NHiroshi DOYU <hdoyu@nvidia.com>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>