config: reorder the architectures sub-menu

Re-organise the sub-menu so that:
- the archs list comes first,
- followed by archs generic options
- followed by archs specific options

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

 reporter_name="Alexander BIGGA"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-07/msg00000.html"

 reporter_comment=""