cc/gcc: backport upstream fix for GCC 4.7.0 bug 54494

See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54494, also has a serious
impact on the Linux/MIPS kernel build.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

 reporter_name="Julien DUSSER"

 reporter_url="http://sourceware.org/ml/crossgcc/2008-10/msg00054.html"

 reporter_comment="Soft-float for the 405 PowerPC"