drm/i915/skl: Skylake also supports DP MST
drm/i915/skl: Skylake also supports DP MST

I've checked that TRANS_DDI_MODE, DP_TP_CTL MST bits are identical to
HSW/BDW on SKL, as well as the long vs short HPD bits. So we have a good
chance to be working as well as prevous platforms.

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>
Reviewed-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs