Platform: Use psa_key_bits_t when dealing with key sizes

When dealing with key sizes in bits and builtin keys, use
the recommended type psa_key_bits_t instead of a more
generic size_t type

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: I047d81917d2fccb845b5e5074c31125ba3156666
5 files changed