Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "6 fixes"

* emailed patches from Andrew Morton <[email protected]>:
  drivers core: remove assert_held_device_hotplug()
  mm: add private lock to serialize memory hotplug operations
  mm: don't warn when vmalloc() fails due to a fatal signal
  mm, x86: fix native_pud_clear build error
  kasan: add a prototype of task_struct to avoid warning
  z3fold: fix spinlock unlocking in page reclaim