Revert "Revert "ARM: 7169/1: topdown mmap support""

This reverts commit f27e4f0e730b99ca4dabed0b408d96dbf73a8fac.

An alternate fix has been proposed where userspace programs
set ADDR_COMPAT_LAYOUT. Bring back the topdown mmap support.

Change-Id: Ibd6e74d406db3a5ddb609e2d2a7a6e9dc2080eca
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 84560dc..7b6f42a 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -313,6 +313,7 @@
  * We provide our own arch_get_unmapped_area to cope with VIPT caches.
  */
 #define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
 
 /*
  * remap a physical page `pfn' of size `size' with page protection `prot'