drm/i915: Switch over to the LLC/eLLC hotspot avoidance hash mode for CCS

Use the LLC/eLLC hotspot avoidance mode for CCS on LLC machines. This is
reported to give better performance.

Testing has indicated that we don't need to enforce any massive 2 or 4
MiB alignment for all compressed resources even though there are still
plenty of stale comments in the spec suggesting that we do.

We do need to make sure every hardware unit that deals with the
compressed data uses the same hash mode.

Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Daniel Stone <daniels@collabora.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170824191100.10949-4-ville.syrjala@linux.intel.com
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>