i965/skl: Use more compact hiz dimensions

i965/skl: Use more compact hiz dimensions

I meant to do this here, but it was in the wrong place:

commit c1151b18f2dce7c6f238f057e9c4fa8d912ce6b5
Author: Ben Widawsky <benjamin.widawsky@intel.com>
Date:   Wed Jun 24 20:07:54 2015 -0700

   i965/skl: Use more compact hiz dimensions

NOTE: Jordan did go back and look at the original mailing list post. I mailed
the right thing, and pushed the wrong one.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Neil Roberts <neil@linux.intel.com>