ssl: improve/fix definitions for internal helpers

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/include/mbedtls/ssl_ciphersuites.h b/include/mbedtls/ssl_ciphersuites.h
index 9c07c54..7df3ec3 100644
--- a/include/mbedtls/ssl_ciphersuites.h
+++ b/include/mbedtls/ssl_ciphersuites.h
@@ -364,25 +364,28 @@
 #define MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED
 #endif
 
-/* TLS 1.2 key exchanges using ECDH(E)*/
+/* TLS 1.2 key exchanges using ECDH or ECDHE*/
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_ENABLED) || \
     defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDHE_ENABLED)
 #define MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED
 #endif
 
-/* TLS 1.2 or 1.3 key exchanges using ECDH(E) */
+/* TLS 1.3 key exchanges using ECDH or ECDHE */
+#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED) && \
+    defined(PSA_WANT_ALG_ECDH)
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_ECDHE_ENABLED
+#endif
+
+/* TLS 1.2 or 1.3 key exchanges using ECDH or ECDHE */
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED) || \
-    (defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) || \
-    defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED)) && \
-    !defined(PSA_WANT_ALG_FFDH)
+    defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_ECDHE_ENABLED)
 #define MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_ANY_ENABLED
 #endif
 
-/* TLS 1.2 or 1.3 DH key exchanges: ECDH(E) or FFDH */
-#if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED) || \
-    defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED) || \
-    defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED)
-#define MBEDTLS_KEY_EXCHANGE_SOME_DH_ANY_ENABLED
+/* TLS 1.2 XXDH key exchanges: ECDH or ECDHE or FFDH */
+#if (defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_1_2_ENABLED) || \
+    defined(MBEDTLS_KEY_EXCHANGE_SOME_DHE_ENABLED))
+#define MBEDTLS_KEY_EXCHANGE_SOME_XXDH_1_2_ENABLED
 #endif
 
 typedef struct mbedtls_ssl_ciphersuite_t mbedtls_ssl_ciphersuite_t;