boot/optee-os: bump to version 3.16.0

Bump OP-TEE OS package version to OP-TEE release 3.16.0 and set
BR2_TARGET_OPTEE_OS_LATEST to select
BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_CRYPTOGRAPHY since
python-cryptography is now needed to build optee-os.

Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>