Use our old mm codebase (based on v3.10) and push in changes that are required
to make it compile with v4.8's header files. To make this work I pulled in
3.10's slab_def.h to kick out 4.8's slab_def.h

The changes are not that significant
* Removed struct slab, struct slab_rcu (Use struct page instead)
* Few kmem_chg related APIs were changed
* Some minor optimizations

Merged from
45eed508 slab: remove SLAB_LIMIT
16025177 slab: remove kmem_bufctl_t
b1cb0982 slab: change the management method of free objects of the slab
a57a4988 slab: use __GFP_COMP flag for allocating slab pages
56f295ef slab: use well-defined macro, virt_to_slab()
68126702 slab: overloading the RCU head over the LRU for RCU free
07d417a1 slab: remove cachep in struct slab_rcu
1ea991b0 slab: remove nodeid in struct slab
ac2b54ed slab: remove colouroff in struct slab
0c3aa83e slab: change return type of kmem_getpages() to struct page
73293c2f slab: correct pfmemalloc check
276a2439 mm/slab: Give s_next and s_stop slab-specific names
e25839f6 mm/slab: Sharing s_next and s_stop between slab and slub
0fa8103b

 mm/slab: Fix drain freelist excessively

Signed-off-by: Vikram Narayanan <vikram186@gmail.com>