cc/gcc: remove duplicate code in core pass-1

Whatever the threading model (NPTL, LT...), we build the same
core pass-1 compiler, so there is no need to have a case-esac
construct.

Remove now mis-leading and incorect comment.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 reporter_name="Gustavo Zacarias <gustavo@zacarias.com.ar>"

 reporter_url="http://sourceware.org/ml/crossgcc/2011-03/msg00028.html"

 reporter_comment=""