Build: Clean up mbedcrypto related CMakeLists.txt

Simplify dependencies and use consistent style for mbedTLS
related targets both in BL2 and TF-M Crypto.

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I45b53a3ec18f34670560f20c2151a8c5e8d6f7c6
2 files changed