i965/blorp: Use IMS layout when texturing from depth/stencil surfaces.

i965/blorp: Use IMS layout when texturing from depth/stencil surfaces.

Previously, on Gen7, when texturing from a depth or stencil surface,
the blorp engine would configure the 3D pipeline as though the input
surface was non-multisampled, and perform the necessary coordinate
transformations in the fragment shader to account for the IMS layout.
This meant outputting a lot of extra fragment shader code, and it
raised some uncertainty about how to deal with very large surfaces.

This patch modifies blorp to configure the 3D pipeline properly for
IMS layout when reading from depth and stencil surfaces.

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>