[MIPS] Add missing braces to pte_mkyoung

Only the version pte_mkyoung for 36-bit pagetables on 32-bit hw was
affected and with this bug being around since November 29, 2004 there
is evidence to suport the assumption it was benign ;-)
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

include/asm-mips/pgtable.h

@@ -239,9 +239,10 @@ static inline pte_t pte_mkdirty(pte_t pte)
 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	pte.pte_low |= _PAGE_ACCESSED;
-	if (pte.pte_low & _PAGE_READ)
+	if (pte.pte_low & _PAGE_READ) {
 		pte.pte_low  |= _PAGE_SILENT_READ;
 		pte.pte_high |= _PAGE_SILENT_READ;
+	}
 	return pte;
 }
 #else