i965: Fix fast depth clears for surfaces with a dimension of 16384.

i965: Fix fast depth clears for surfaces with a dimension of 16384.

I hadn't bothered to set this bit because I figured it would just
paper over us getting the rectangle wrong.  But it turns out that
there is a legitimate reason to use it, so let's do so.

The alternative would be to chop up 16k clears to multiple 8k clears,
which is pointlessly painful.

Cc: "17.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Nanley Chery <nanley.g.chery@intel.com>