meta: Fold the texture setup into setup_copypix_texture().

meta: Fold the texture setup into setup_copypix_texture().

There was this funny argument passed to setup for "did alloc decide we
need to allocate new texture storage?", which goes away if we don't have
the caller do alloc as a separate step.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>