Instead of looping through all CRTCs, update DDL for current CRTC for which
watermark is being updated.
CHV is confirmed to have precision of 32/64 which is same as VLV.
Reviewed-by: Imre Deak <imre.deak@intel.com> Signed-off-by: Gajanan Bhat <gajanan.bhat@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>