Only include config_psa.h from config.h with new-style PSA configuration
Only include config_psa.h from config.h with new-style PSA configuration

In old-style configuration, do not include mbedtls/config_psa.h from
mbedtls/config.h.

The inclusion should not and did not break any code, but it caused our
testing to miss a break of backward compatibility (fixed in "Include
config_psa.h from psa/crypto.h"). If users have their own config.h
which enabled MBEDTLS_PSA_CRYPTO_C and worked prior to the creation of
config_psa.h and MBEDTLS_PSA_CRYPTO_CONFIG, their config.h must keep
working. By including config_psa.h from config.h in the legacy case,
we weren't testing the legacy configuration mechanism adequately.

Signed-off-by: Gilles Peskine <f805f64266d288fc5467baa7be6cd0ff366f477b@arm.com>

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