mm: reintroduce the config ARCH_HAS_ELF_RANDOMIZE

Config ARCH_HAS_ELF_RANDOMIZE is originally introduced in
'commit 2b68f6caeac2 ("mm: expose arch_mmap_rnd when available")'.
It got deleted while resolving some merge conflicts.
Adding it again to fix CTS issue.

Change-Id: I99e45144536bdb68b0690a978fabc9c09540674d
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>