Add missing platform information for KBL

Add missing platform information for KBL

In testing KBL, I found:

 - urb size was not set for slices gt1.5, gt2, and gt3.  The value I
   used for these slices (384) was taken from an earlier patch authored
   by Ben Widawsky.

 - slice count was missing.  This field was added by
   a403ad4f5a034e52a3cd845e91c4aa3e6927b731

With this commit, KBL passes piglit at parity with SKL.

Note: As requested by Kristian, Sarah modified this patch to drop
setting urb size for gt1.5, gt2, and gt3, since the correct default is
set in the GEN9 macro by commit c1e38ad37042b0ec261eb0ba5631b7ff0ee7a9da
"i965/skl: Use larger URB size where available."

Signed-off-by: Mark Janes <mark.a.janes@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Reviewed-by: Kristian Høgsberg Kristensen <kristian.h.kristensen@intel.com>
Cc: "11.1" <mesa-stable@lists.freedesktop.org>