test_suite_x509write: use psa_hash_compute() instead mbedtls_md()
test_suite_x509write: use psa_hash_compute() instead mbedtls_md()

Signed-off-by: Przemek Stekiel <1d381786fa074b2f2333843496828c8e4357e75f@mobica.com>

Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls