drm/i915: Show dmc debug registers on Kabylake

The assumption is that the registers offsets are
identical as with skl. Also all the published
kbl firmwares support the debug registers. So
let kbl show the debug counts.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100975


Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1494324322-28193-1-git-send-email-mika.kuoppala@intel.com