KSM: Add auto flag new VMA as VM_MERGEABLE

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
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>
KSM: mark_new_vma added to Documentation.

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
Merge branch 'xxhash' into ksm_xxhash
KSM: Added xxhash

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