Introduce and use MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED

Introduce and use
MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED to
guard TLS code (both 1.2 and 1.3) specific
to handshakes involving PSKs.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/include/mbedtls/ssl_ciphersuites.h b/include/mbedtls/ssl_ciphersuites.h
index 6682ee8..b46116e 100644
--- a/include/mbedtls/ssl_ciphersuites.h
+++ b/include/mbedtls/ssl_ciphersuites.h
@@ -346,6 +346,11 @@
 #define MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED
 #endif
 
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) || \
+    defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
+#define MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED
+#endif
+
 /* Key exchanges using DHE */
 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)       || \
     defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)