binutils/binutils: do not forget to extract elf2flt

In case we're using a custom (aka local) binutils source, we still
need to extract and patch elf2flt.

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

 reporter_name="Kevin Cernekee"

 reporter_url="http://sourceware.org/ml/crossgcc/2011-09/msg00037.html"

 reporter_comment="MIPS SDE-compatible toolchain"