gcc-4.7/gcc: disable sdt from configure.ac to keep compatibility with configure

gcc-4.7/gcc: disable sdt from configure.ac to keep compatibility with configure

We had disabled the sdt from configure, let's also disable it from
confgure.ac to keep them compatible.

BTW, the libstdc++-v3 of gcc-4.7 doesn't use the sdt, so we don't need
to edit libstdc++-v3/configure as gcc-4.8.

NOTE, this commit edit the patch gcc-4.7/disablesdt.patch directly.

[YOCTO #5657]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>