linux-image 4.3.3 bcache stability patches

[Martin Kokes <shr3k@typo3-hosting.com>]

Hello list, Ben,

Would it be possible to include latest bcache stability patches from 
https://github.com/torvalds/linux/compare/master...ewheelerinc:bcache-patches-for-3.17 
According bcache developers (Kent Overstreet and others) it merges fine 
from 3.17 up to 4.4 as they concerns only bcache driver:

bcache/btree.c
bcache/super.c
bcache/writeback.c
bcache/writeback.h

see https://lkml.org/lkml/2015/12/29/379

This should improve SSD lockups.

Thank you

Martin