ssl.h: use PSA hash buffer size when PSA is used

Signed-off-by: Przemyslaw Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 0fcac68..1e0220a 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -629,7 +629,12 @@
 
 #define MBEDTLS_PREMASTER_SIZE     sizeof( union mbedtls_ssl_premaster_secret )
 
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#define MBEDTLS_TLS1_3_MD_MAX_SIZE         PSA_HASH_MAX_SIZE
+#else
 #define MBEDTLS_TLS1_3_MD_MAX_SIZE         MBEDTLS_MD_MAX_SIZE
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 
 /* Length in number of bytes of the TLS sequence number */
 #define MBEDTLS_SSL_SEQUENCE_NUMBER_LEN 8