autotools: Add passes.h to sources so it will be included in the tarball
This was introduced in commit 8f848ada but not added to the sources list, which is necessary for it to be included in release tarballs. Fixes: 8f848ada ("swr/rast: Start refactoring of builder/packetizer.") Signed-off-by:Dylan Baker <dylan.c.baker@intel.com> Reviewed-by:
Kenneth Graunke <kenneth@whitecape.org>