powerpc/fsl_booke: protect the access to MAS7

The e500v1 doesn't implement the MAS7, so we should avoid to access
this register on that implementations. In the current kernel, the
access to MAS7 are protected by either CONFIG_PHYS_64BIT or
MMU_FTR_BIG_PHYS. Since some code are executed before the code
patching, we have to use CONFIG_PHYS_64BIT in these cases.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

arch/powerpc/kernel/head_fsl_booke.S

@@ -82,7 +82,9 @@ _ENTRY(_start);
 	and	r19,r3,r18		/* r19 = page offset */
 	andc	r31,r20,r18		/* r31 = page base */
 	or	r31,r31,r19		/* r31 = devtree phys addr */
+#ifdef CONFIG_PHYS_64BIT
 	mfspr	r30,SPRN_MAS7
+#endif
 
 	li	r25,0			/* phys kernel start (low) */
 	li	r24,0			/* CPU number */

arch/powerpc/mm/hugetlbpage-book3e.c

@@ -103,7 +103,8 @@ void book3e_hugetlb_preload(struct vm_area_struct *vma, unsigned long ea,
 	if (mmu_has_feature(MMU_FTR_USE_PAIRED_MAS)) {
 		mtspr(SPRN_MAS7_MAS3, mas7_3);
 	} else {
-		mtspr(SPRN_MAS7, upper_32_bits(mas7_3));
+		if (mmu_has_feature(MMU_FTR_BIG_PHYS))
+			mtspr(SPRN_MAS7, upper_32_bits(mas7_3));
 		mtspr(SPRN_MAS3, lower_32_bits(mas7_3));
 	}