mbedtls: use one AES table per direction

MBEDTLS_AES_FEWER_TABLES keeps one 1 KB table per direction and rotates
its entries at run time instead of storing four rotated copies. Firmware
size: Feather ESP32-C6 -5,648 bytes, Pico W -5,928 bytes, Pico 2 W
-6,144 bytes.

On ESP32 the TLS traffic is encrypted by the AES peripheral, so only
mbedtls's software paths use the tables. On a PicoPad (RP2040), where
TLS runs software AES, a 1 MB HTTPS download ran at 320 kB/s with the
change and 316 kB/s without (medians), and the handshake took the same
3.8 s.

Author: lynt-smitka

lib/mbedtls_config/tf_psa_crypto_config.h

@@ -45,6 +45,7 @@ void m_tracked_free(void *ptr);
 // Size/speed tradeoffs ///////////////////////////////////////////////////////
 
 #define MBEDTLS_AES_ROM_TABLES
+#define MBEDTLS_AES_FEWER_TABLES
 #define MBEDTLS_SHA256_SMALLER
 #define MBEDTLS_ECP_NIST_OPTIM
 

ports/espressif/esp-idf-config/sdkconfig.defaults

@@ -121,6 +121,7 @@ CONFIG_MBEDTLS_SSL_PROTO_DTLS=y
 # CONFIG_MBEDTLS_ECP_DP_BP512R1_ENABLED is not set
 # CONFIG_MBEDTLS_ECP_FIXED_POINT_OPTIM is not set
 CONFIG_MBEDTLS_ERROR_STRINGS=y
+CONFIG_MBEDTLS_AES_FEWER_TABLES=y
 # end of mbedTLS
 
 #