[POWERPC] 8xx: platform specific mmu updates

This is just a straight port of the same done in arch/ppc
by Marcelo Tosatti. One used to be
[PATCH] ppc32 8xx: update_mmu_cache() needs unconditional tlbie,
commit eb07d964b4491d1bb5864cd3d7e7633ccdda9a53

In a nutshell, the board is nearly stuck without this, yet without any
visible failure - being just very slow.

Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/mm/mem.c

@@ -490,19 +490,19 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 	    !cpu_has_feature(CPU_FTR_NOEXECUTE) &&
 	    pfn_valid(pfn)) {
 		struct page *page = pfn_to_page(pfn);
+#ifdef CONFIG_8xx
+		/* On 8xx, cache control instructions (particularly
+		 * "dcbst" from flush_dcache_icache) fault as write
+		 * operation if there is an unpopulated TLB entry
+		 * for the address in question. To workaround that,
+		 * we invalidate the TLB here, thus avoiding dcbst
+		 * misbehaviour.
+		 */
+		_tlbie(address);
+#endif
 		if (!PageReserved(page)
 		    && !test_bit(PG_arch_1, &page->flags)) {
 			if (vma->vm_mm == current->active_mm) {
-#ifdef CONFIG_8xx
-			/* On 8xx, cache control instructions (particularly 
-		 	 * "dcbst" from flush_dcache_icache) fault as write 
-			 * operation if there is an unpopulated TLB entry 
-			 * for the address in question. To workaround that, 
-			 * we invalidate the TLB here, thus avoiding dcbst 
-			 * misbehaviour.
-			 */
-				_tlbie(address);
-#endif
 				__flush_dcache_icache((void *) address);
 			} else
 				flush_dcache_icache_page(page);