intel: Fix software copying of miptree faces for weird formats.

intel: Fix software copying of miptree faces for weird formats.

Now that we have W-tiled S8, we can't just region_map and poke at bits --
there has to be some swizzling.  Rely on intel_miptree_map to get that job
done.  This should also get the highest performance path we know of for the
mapping (interesting if I get around to finishing movntdqa some day).

v2: Fix stale name of the bit in a comment.

Reviewed-by: Chad Versace <chad.versace@linux.intel.com>