Merge tag 'drm-intel-fixes-2015-03-12' of git://anongit.freedesktop.org/drm-intel into drm-fixes

More i915 fixes, three out of four are fixes to old bugs, cc: stable.

* tag 'drm-intel-fixes-2015-03-12' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Prevent TLB error on first execution on SNB
  drm/i915: Do both mt and gen6 style forcewake reset on ivb probe
  drm/i915: Make WAIT_IOCTL negative timeouts be indefinite again
  drm/i915: use in_interrupt() not in_irq() to check context