pre-test version of the mbedtls_ssl_conf_rng removal

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index 84d5994..d3c4223 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -2133,14 +2133,14 @@
     MBEDTLS_SSL_DEBUG_MSG(3, ("server hello, current time: %" MBEDTLS_PRINTF_LONGLONG,
                               (long long) t));
 #else
-    if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 4)) != 0) {
+    if ((ret = psa_generate_random(ssl->conf->p_rng, p, 4)) != 0) {
         return ret;
     }
 
     p += 4;
 #endif /* MBEDTLS_HAVE_TIME */
 
-    if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 20)) != 0) {
+    if ((ret = psa_generate_random(p, 20)) != 0) {
         return ret;
     }
     p += 20;
@@ -2166,7 +2166,8 @@
     } else
 #endif
     {
-        if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, p, 8)) != 0) {
+	    
+        if ((ret = psa_generate_random(p, 8)) != 0) {
             return ret;
         }
     }
@@ -2197,7 +2198,7 @@
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
         {
             ssl->session_negotiate->id_len = n = 32;
-            if ((ret = ssl->conf->f_rng(ssl->conf->p_rng, ssl->session_negotiate->id,
+            if ((ret = psa_generate_random(ssl->session_negotiate->id,
                                         n)) != 0) {
                 return ret;
             }