package/setools: remove C++ dependency on comment

package/setools: remove C++ dependency on comment

Bump to 4.1.1 (commit 96d3d017963b) removed setools' dependency on
BR2_INSTALL_LIBSTDCPP, but the corresponding inverse dependency on one
of its Kconfig comment was not removed. This led to have the package
being available while a Kconfig comment on non-matched dependencies is
shown. Fix this by removing the dependency on !BR2_INSTALL_LIBSTDCPP on
the Kconfig comment.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>