drm/i915: Remove reset_counter from intel_crtc.

With the removal of cs-based flips all mmio waits will
finish without requiring the reset counter, because the
waits will complete during gpu reset.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463490484-19540-16-git-send-email-maarten.lankhorst@linux.intel.com


Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>