- MBEDTLS_GENPRIME is removed because now we rely on predefined
RSA keys.
- MBEDTLS_RSA_GEN_KEY_MIN_BITS is replaced with RSA_KEY_SIZE which
is set on top of test_suite_pk to a value which is supported
in the predefined_keys[] array.
Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>