i965: Don't rely on nir for uses_texture_gather

When a program is restored from the shader cache, prog->nir will be
NULL, but prog->info will be restored.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
3 files changed