[S390] 4level-fixup cleanup

Get independent from asm-generic/4level-fixup.h

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index dc37ea8..7e8efaa 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -18,13 +18,18 @@
 static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr)
 {
 	pgd_t *pgd;
+	pud_t *pud;
 	pmd_t *pmd;
 
 	pgd = pgd_offset(mm, addr);
 	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
 		return NULL;
 
-	pmd = pmd_offset(pgd, addr);
+	pud = pud_offset(pgd, addr);
+	if (pud_none(*pud) || unlikely(pud_bad(*pud)))
+		return NULL;
+
+	pmd = pmd_offset(pud, addr);
 	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
 		return NULL;