staging: tidspbridge: add pud code

And fix the following warning for passing an incorrect
variable type.

../tiomap3430.c: In function 'user_va2_pa':
../tiomap3430.c:1555:
    warning: passing argument 1 of 'pmd_offset' from
    incompatible pointer type
arch/arm/include/asm/pgtable-2level.h:156:
    note: expected 'struct pud_t *' but argument is of
    type 'pmdval_t (*)[2]'

While at it, eliminate 'if' nesting to increase readability.
Signed-off-by: Omar Ramirez Luna <omar.ramirez@copitl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/tidspbridge/core/tiomap3430.c

@@ -1547,21 +1547,28 @@ static int bridge_brd_mem_un_map(struct bridge_dev_context *dev_ctxt,
 static u32 user_va2_pa(struct mm_struct *mm, u32 address)
 {
 	pgd_t *pgd;
+	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *ptep, pte;
 
 	pgd = pgd_offset(mm, address);
-	if (!(pgd_none(*pgd) || pgd_bad(*pgd))) {
-		pmd = pmd_offset(pgd, address);
-		if (!(pmd_none(*pmd) || pmd_bad(*pmd))) {
+	if (pgd_none(*pgd) || pgd_bad(*pgd))
+		return 0;
+
+	pud = pud_offset(pgd, address);
+	if (pud_none(*pud) || pud_bad(*pud))
+		return 0;
+
+	pmd = pmd_offset(pud, address);
+	if (pmd_none(*pmd) || pmd_bad(*pmd))
+		return 0;
+
 	ptep = pte_offset_map(pmd, address);
 	if (ptep) {
 		pte = *ptep;
 		if (pte_present(pte))
 			return pte & PAGE_MASK;
 	}
-		}
-	}
 
 	return 0;
 }