gitignore: be more specific with scripts

  Do not ignore the entire scripts tree, but only
  the ones that menuconfig modifies.

Signed-off-by: KhasMek <Boushh@gmail.com>
tvin: update headers

  From arm-src-kernel-2014-05-26-c53de253cb

Signed-off-by: KhasMek <Boushh@gmail.com>