boot/optee-os: add support to build with python-cryptography

Newer version of optee-os (>= 3.16) uses python-cryptography instead of
python-pycryptodomex in python scripts. Add support to build these
newer versions by adding a new
BR2_TARGET_OPTEE_OS_NEEDS_PYTHON_CRYPTOGRAPHY option which will
select host-python-cryptography dependency when building optee-os.

Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
[yann.morin.1998@free.fr:
  - move the _ARCH_DEPENDS option from the main symbol to thus new
    symbol
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>