gen7: Use logical, not physical, dims in 3DSTATE_DEPTH_BUFFER (v2)

gen7: Use logical, not physical, dims in 3DSTATE_DEPTH_BUFFER (v2)

In 3DSTATE_DEPTH_BUFFER, we set Width and Height to the miptree slice's
physical dimensions. (Logical and physical dimensions may differ for
multisample surfaces).

However, in SURFACE_STATE, we always set Width and Height to the slice's
logical dimensions. We should do the same for 3DSTATE_DEPTH_BUFFER,
because the hw docs say so.

No Piglit regressions (-x glx -x glean) on Ivybridge with Wayland.

v2: No Piglit regressions, for real this time.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>