mbedtls: auto-select MBEDTLS_CIPHER_AES_ENABLED when built-in in PSA

Auto-select MBEDTLS_CIPHER_AES_ENABLED when AES support is requested
through PSA (i.e. CONFIG_PSA_WANT_KEY_TYPE_AES) and the PSA support is
provided through Mbed TLS itself (i.e. CONFIG_MBEDTLS_PSA_CRYPTO_C).

This mimic what happens in Mbed TLS at build time: if AES support
is required through PSA, but there's no one else providing it
(i.e. no TF-M in Zephyr) then provide this support through legacy
AES module.

This is useful in samples/tests so that the user can simply use the
PSA_WANT symbol to ask for AES support in PSA crypto and then tune
the AES features (ex: CONFIG_MBEDTLS_AES_ROM_TABLES) without the need
to also define CONFIG_MBEDTLS_CIPHER_AES_ENABLED.

Signed-off-by: Valerio Setti <[email protected]>

modules/mbedtls/Kconfig.tls-generic

@@ -246,6 +246,7 @@ config MBEDTLS_SOME_CIPHER_ENABLED
 
 config MBEDTLS_CIPHER_AES_ENABLED
 	bool "AES block cipher"
+	default y if PSA_WANT_KEY_TYPE_AES && MBEDTLS_PSA_CRYPTO_C
 
 if MBEDTLS_CIPHER_AES_ENABLED