i965/gen9: Add hs, ds, and cs thread + urb info

i965/gen9: Add hs, ds, and cs thread + urb info

For SKL: These are the production values.

For BXT: These are low estimates to enable platforms.

This patch was originally part of
i965/skl: Add production thread counts and URB size
but was split out at Jordan's request (which I found to be reasonable).

Note on stable inclusion: 10.6 does not care about hs, and ds. It does care
about cs, but since Jordan was the one that asked me to extract it, I'll leave
it up to him to deal with a backport to stable is required.

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