KSM: Add to sysfs - mark_new_vma

It allow to control user mark new vma as VM_MERGEABLE or not

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
KSM: Add config to control mark_new_vma

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>