The function was removed in:
commit 0e32b39cee
Author: Dave Airlie <airlied@redhat.com>
Date: Fri May 2 14:02:48 2014 +1000
drm/i915: add DP 1.2 MST support (v0.7)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>