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>