isl/state: Use the layout for computing qpitch rather than dimensions

isl/state: Use the layout for computing qpitch rather than dimensions

For depth/stencil 1-D textures on SKL, we want them layed out in the old
format that has been used since gen4.  In order for the surface state
fill-out code to handle, this it needs to distinguish based on layout
rather than just dimensionality.

Reviewed-by: Chad Versace <chad.versace@intel.com>
Cc: "12.0" <mesa-stable@lists.freedesktop.org>