powerpc: Fix pte_update for CONFIG_PTE_64BIT and !PTE_ATOMIC_UPDATES

Because the pte is now 64-bits the compiler was optimizing the update
to always clear the upper 32-bits of the pte.  We need to ensure the
clr mask is treated as an unsigned long long to get the proper behavior.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

include/asm-powerpc/pgtable-ppc32.h

@@ -624,7 +624,7 @@ static inline unsigned long long pte_update(pte_t *p,
 	: "cc" );
 #else /* PTE_ATOMIC_UPDATES */
 	unsigned long long old = pte_val(*p);
-	*p = __pte((old & ~clr) | set);
+	*p = __pte((old & ~(unsigned long long)clr) | set);
 #endif /* !PTE_ATOMIC_UPDATES */
 
 #ifdef CONFIG_44x