Merge tag 'drm-amdkfd-fixes-2015-07-09' of git://people.freedesktop.org/~gabbayo/linux into drm-fixes

A single fix so far for 4.2:
- checking a pointer is not null before using it

* tag 'drm-amdkfd-fixes-2015-07-09' of git://people.freedesktop.org/~gabbayo/linux:
  drm/amdkfd: validate pdd where it acquired first