i965: Make intel_set_texture_region just take a BO and pitch.

i965: Make intel_set_texture_region just take a BO and pitch.

I want to do this to get the region removed from DRI images.  However, it
does mean that we won't share the intel_region between the rb and the
texture for texture_from_pixmap.  I think that's fine.

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