As we are about to bump the optee-test package to 3.11.0, which
requires C++ support, let's enable C++ support in the
qemu_arm_vexpress_tz_defconfig, which uses optee-test.
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
