misc i915 fixes
* tag 'drm-intel-fixes-2015-01-15' of git://anongit.freedesktop.org/drm-intel:
drm/i915: Fix mutex->owner inspection race under DEBUG_MUTEXES
drm/i915: Ban Haswell from using RCS flips
drm/i915: vlv: sanitize RPS interrupt mask during GPU idling
drm/i915: fix HW lockup due to missing RPS IRQ workaround on GEN6
drm/i915: gen9: fix RPS interrupt routing to CPU vs. GT