intel/compiler: Avoid false positive assertions

intel/compiler: Avoid false positive assertions

A follow on patch will move the 'nr' field to the union containing the
immediate field, so prepare by checking that we're only testing these
assertions if the .file is correct.

The assertions with != ARF were kind of silly to begin with because the
<128 check is specifically only for things in the GRF.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>