cc/gcc: only build required core passes

We now know exactly what pass to build, so build only what is required.

Reported-by: Trevor Woerner <trevor.woerner@linaro.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 # Compute sparc-specific values

 CT_DoArchTupleValues() {

     # That's the only thing to override

     if [ "${CT_ARCH_64}" = "y" ]; then

         CT_TARGET_ARCH="sparc64${CT_ARCH_SUFFIX}"

     fi

 }