i965: Drop use of intel_region from miptrees.

i965: Drop use of intel_region from miptrees.

Note: region->width/height used to reflect the total_width/height padding
of separate stencil, though mt->total_width didn't.  region->width/height
was being used in EGL images, where the padded value would have been the
wrong one, so I converted them to use rb->Width/Height.

v2: Drop debug printf that slipped in (caught by Ken)

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>