ppc/85xx: Ensure that MAS8 is zero when writing TLB entries.

Its reset value is random, and we sometimes read uninitialized TLB
arrays.  Make sure that we don't retain MAS8 from reading such an entry
if the VF bit in MAS8 is set, attempts to use the mapping will trap.

Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/include/asm-ppc/processor.h b/include/asm-ppc/processor.h
index 0a4c66c..3764a5a 100644
--- a/include/asm-ppc/processor.h
+++ b/include/asm-ppc/processor.h
@@ -518,6 +518,7 @@
 #define SPRN_MAS5	0x275	/* MMU Assist Register 5 */
 #define SPRN_MAS6	0x276	/* MMU Assist Register 6 */
 #define SPRN_MAS7	0x3B0	/* MMU Assist Register 7 */
+#define SPRN_MAS8	0x155	/* MMU Assist Register 8 */
 
 #define SPRN_IVOR32	0x210	/* Interrupt Vector Offset Register 32 */
 #define SPRN_IVOR33	0x211	/* Interrupt Vector Offset Register 33 */
@@ -720,6 +721,7 @@
 #define MAS5	SPRN_MAS5
 #define MAS6	SPRN_MAS6
 #define MAS7	SPRN_MAS7
+#define MAS8 	SPRN_MAS8
 
 #if defined(CONFIG_4xx) || defined(CONFIG_44x) || defined(CONFIG_MPC85xx)
 #define DAR_DEAR DEAR